what is the number of shells and number of valence electrons for the following elements: Na, O, I, Ca
The number of electrons present in the outermost shell is called valence electrons.
What are valence electrons?The number of electrons present in the last shell is called valence electrons. The atomic number of sodium is 11 and the atomic number of oxygen is 8.
There is 1 valence electron in sodium. The number of valence electrons in oxygen is 2.
The atomic number of iodine is 53. The number of the valence electron in iodine is 1. The atomic number of calcium is 20. The valence electron in calcium is 2.
Therefore, The number of electrons present in the outermost shell is called valence electrons.
To know more about valency, refer to the link:
https://brainly.com/question/12744547
#SPJ1
An Element is any naturally occurring substance found on Earth, they are
normally identified by
a) Atomic Mass
b) Density
c) Group and Period Number
d) Atomic Number
An element is any naturally occurring substance found on Earth that is normally identified by the atomic number (option D).
What is an element?An element is the simplest chemical substances that cannot be decomposed in a chemical reaction or by any chemical means and made up of atoms all having the same number of protons.
Chemical elements are arranged in accordance with their atomic numbers on the periodic table.
Each element has its own unique symbol but are usually identified by its atomic number. All elements possess its own atomic number.
Therefore, an element is any naturally occurring substance found on Earth that is normally identified by the atomic number.
Learn more about elements at: https://brainly.com/question/20573603
#SPJ1
85% of Greenland is covered in ice with an average thickness of 1500 meters. Estimate how much ice (in kg) there is in Greenland if the island is approximately 840000 square miles. For this problem, assume the density of ice is exactly 0.917 g/mL, and that one mile is exactly 1.60 kilometers.
1375.5 kg ice (in kg) there is in Greenland if the island
Given data is 85% of Greenland is covered in ice thickness = 1500 meters 840000 square miles, density = 0.917 g/mL, one mile = 1.60 kilometers.
Here 1.60 kilometers = 0.6177 square miles we have to find ice (in kg) = ?
Here density is given and thickness also given means volume so we have to find mass in kg = ?
Density = mass/volume
0.917 g/mL = mass/ 1500
Mass = 0.917 g/mL× 1500
Mass = 1375.5 kg of ice there is in Greenland if the island
Know more about ice of Greenland
https://brainly.com/question/28646676
#SPJ1
Which graph best represents the relationship between the mass and volume of various-sized pieces of this material
The relationship between the volume and the mass of the object is shown by option A.
What is density?Density gives the ratio of the mass to the volume of an object. We know that volume is an intrinsic property. This implies that it does not change with the amount of the substance. It can be used to identify a given substance because it does not change with the mass or the quantity of the substance present.
It is possible to see that the relationship between the volume and the mass of the object. This relationship is based on the density of the object that is under consideration. The first question that we would have to ask is if the volume changes with the mass of the object.
Given the fact that we have established that the ratio of the mass to the volume of a body is always a constant, we can conclude that the mass does not undergo any change with the volume of the object.
We can conclude that the relationship between the volume and the mass of the object is shown by option A.
Learn more about density:https://brainly.com/question/15164682
#SPJ1
ch4 2o2 → co2 2h2o 4 moles of methane (ch4) are combined with 5 moles of oxygen (o2). how much carbon dioxide (co2) will form? group of answer choices
Only 2.5 moles of CO2 can be produced since oxygen is the limiting reaction.
Steps4molCH4 x (1molCO2/1molCH4) =4 mol CO2
5 mol O2 x (1molCO2/2molO2) =2.5 molCO2
Only 2.5 moles of CO2 can be produced since oxygen is the limiting reaction.
Why is carbon dioxide important? What is it?One carbon atom and two oxygen atoms make up the molecules of carbon dioxide (CO2). An essential greenhouse gas that aids in keeping heat in our atmosphere is carbon dioxide. Our earth would be uninhabitable cold without it.What is carbon dioxide used for?
Co2 is used as a refrigerant, in extinguishers, to blow coal, foam rubber and plastics, inflate life rafts and life jackets, blast coal, promote plant growth in greenhouses, immobilise animals before slaughter, and in carbonated drinks.
learn more about carbon dioxide here
https://brainly.com/question/25385913
#SPJ4
what is the chemical formula of Barium sulfide
Answer:
BaS
Explanation:
The chemical formula of Barium sulfide is BaS. It's molar mass is 169.39 g/mol.
Identify the products in the chemical
equation below. Count the total number of
atoms on the products side of the chemical
equation.
CH3COOH + NaOH → CH3COONa + H₂O
The given chemical reaction between acetic acid and sodium hydroxide has sodium acetate and water as its products.
The balanced equation of a chemical reaction between acetic acid and sodium hydroxide is:
[tex]CH_3COOH (aq) + NaOH (aq) \rightarrow CH_3COONa (aq) + H_2O (l)[/tex]
This reaction is a neutralization reaction between a weak acid (acetic acid) and a strong base (sodium hydroxide).
In a neutralization reaction, an acid and a base mix chemically to provide salt and water as the final products. [tex]H^+[/tex] ions and [tex]OH^-[/tex] ions combine to generate water during a neutralization process. Because acid and base balance each other out to create a neutral chemical, this reaction is therefore known as a neutralization reaction.
In a balanced equation, the number of atoms of each element remains the same before and after the reaction. Therefore, in this reaction, on the products side, the number of atoms of Carbon (C) is 2, Hydrogen (H) is 5, Oxygen (O) is 3 and Sodium (Na) is 1.
Learn more about Acetic acid and Sodium hydroxide here:
https://brainly.com/question/14919219
#SPJ9
What variable stays the same when completing an experiment.
Answer:
control variable
Explanation:
hope this helps :)
PLEASE HELP 10 POINTS
Which of the following is a
reasonable ground-state electron configuration?
1s21p5
1s22s22p8
1s22s22d4
1s22s22p6
The reasonable ground - state electron configuration is 1s² 2s²2p⁶
1) Electron configuration is defined as the arrangement of electron in the atomic orbtials.
2)The ground state electron configuration is lowest energy level and have most stable arrangement.
3) An excited state configuration is a higher energy level.
4) According to Aufbau principle ., electrons will occupy the orbitals of lower energies first then occupying higher energy orbitals.
5) Energy of orbitals is calculated by the sum of principle quantum number and azimuthal quantum numbers.
6) The rule of electron filling in the orbital is from lower energy level to higher energy level.
7) According to this rule electrons are filled in the order of 1s 2s 2p 3s 3p 4s 3d 4p 5s ........and so on.
8) According to pauli principle , maximum two electrons, having opposite spin can fit in orbital.
9) According to Hund's rule , orbital in given sub-shell is singly occupied by electrons before filling second electron in an orbital.
10) The ground state configuration is the arrangement of electron around the nucleus of an atom with lower energy levels.
Hence,The reasonable ground-state electron configuration is 1s² 2s² 2p⁶
To learn more about electronic configuration here
https://brainly.com/question/14283892
#SPJ1
an amphiprotic species must always have a lone pair of valence electrons, and a hydrogen atom that can be donated as a proton (h ). is this statement true or false?
This statement is true.
Amphiprotic species means molecule or ion which can either donate or accept a proton depending on their circumstances. we identify the amphiprotic species it must contain hydrogen atom that can be released a proton. it also must be capable of accepting proton from the compound. amphiprotic species must also have lone pair of valence electron and a hydrogen atom that can be donated as a proton H+
So it is true.
Know more about amphiprotic species.
https://brainly.com/question/28463442
#SPJ4
What is the [H*] in a solution with pOH of 0.253?
A.
B.
OC
OD.
5.58 x 10-15 M
1.79 x 1014 M
3.21 x 102 M
5.58 x 10 M
Answer:
poh = .253
p h2o= p[H+] +P[OH-]
ph2o is 14
14= pH+ + poH
14 = pH+ +.253
14-.253 =pH+
13.747 =ph+
and we know that
log [H+] = -pH+
[H+] = antilog pH+
H+ = antilog 13.747
H+ = 1.79×10-15
1. Most of the chemicals included in your kit can be discarded down a drain with copious amounts of water. Describe a situation in which you would need to neutralize a chemical before discarding down a drain.
Answer:
A strong acid or a strong base should be neutralized before pouring down a drain.
Explanation:
Always make sure to add acid to water (not vice-versa) to avoid a nasty exothermic reaction :)
calculate the mass of dinitrogen tetroxide n2o4 that contains a trillion ×1.001012 nitrogen atoms. be sure your answer has a unit symbol if necessary, and round it to 3 significant digits.
The mass of dinitrogen tetroxide the number of Nitrogen atoms are 46 x 10^9 gram
Given:
number of nitrogen atoms = 1 x 10^12 atoms
To Find:
mass of dinitrogen tetroxide
Solution:
From the molecular formula of dinitrogen tetraoxide;
molar mass of dinitrogen tetraoxide = 92 g/mol
92 g of dinitrogen tetraoxide contains 2 atoms of nitrogen
x g of dinitrogen tetraoxide will contain 1 * 10^12 atoms of nitrogen
x = 92*1* 10^ 9/2
x = 46 x 10^9 gram
Hence, the number of Nitrogen atoms are
Hence, the number of Nitrogen atoms are 46 x 10^9 gram
Learn more about Mass here:
https://brainly.com/question/26150306
#SPJ4
Answer:
The mass of dinitrogen tetroxide the quantity of Nitrogen particles are 46 x 10^9 gram
Number of nitrogen atoms = 1 x 10^12 atoms
Explanation:
From the atomic Formula of dinitrogen tetraoxide;
molar mass of dinitrogen tetraoxide = 92 g/mol
92 g of dinitrogen tetraoxide contains 2 molecules of nitrogen
x g of dinitrogen tetraoxide will contain 1 * 10^12 molecules of nitrogen
x = 92*1* 10^ 9/2
x = 46 x 10^9 gram
the quantity of Nitrogen molecules are 46 x 10^9 gram
A 150. 0 ml sample of an aqueous solution at 25°c contains 15. 2 mg of an unknown nonelectrolyte compound. If the solution has an osmotic pressure of 8. 44 torr, what is the molar mass of the unknown compound?.
Answer:
3.141592653589793238
Explanation:
3.141592653589793238
The molar mass of the unknown compound in the aqueous solution was 223.2 g/mol.
What is osmotic pressure?Osmotic pressure can be described as the minimum pressure requires to be applied to a solution to stop the flow of its pure solvent across a semipermeable membrane. The measurement of the tendency of a solution to take in a pure solvent by osmosis is osmotic pressure.
To determine the molar mass of a compound from the given weight, the concentration of the compound needs to be determined.
π = i ×MRT
8.44 = 1×M× 62.36 ×298
M = 4.54 × 10⁻⁴ M
Given the mass of the unknown compound = 15.2 mg = 0.0152 g
The volume of the compound = 150 ml =0.150 L
From the molarity of the compound, we can determine the molar mass as:
Molarity = mass/(Molar mass × Volume)
Molar mass = mass/(Molarity × Volume)
Molar mass = 0.0152/ (4.54 × 10⁻⁴ × 0.150)
Molar mass = 223.2 g/mol
Learn more about osmotic pressure, here:
https://brainly.com/question/10046758
#SPJ5
Why is the charge of an atom always neutral?
A. same number of protons and neutrons
B. same number of neutrons and electrons
C. equal number of protons, neutrons, and electrons at all times
D. same number protons and electrons
Answer:
D
Explanation:
this is because the number of protons is always equal to the number of electrons of an atom
If a meteorologist says that the air pressure is getting lower, what
would you expect to see happen to Torricelli's mercury barometer?
If the air pressure is reduced, the pointer or hand of the Torricelli's mercury barometer sinks or falls to the bottom.
An inverted (upside-down) glass tube standing in a mercury bath is a Torricellian barometer, also known as a mercury barometer. Some of the mercury's surface particles climb up the tube as a result of air pressure pushing down on it. The mercury rises more rapidly when air pressure increases.
A tall closed tube placed upside-down in a mercury bath, which is a thick liquid metal at room temperature, creates the simplest type of barometer, with the liquid rising partially up the tube as it does in a thermometer. Because mercury is more practical than water for barometers, we utilize it instead. Due to its lower density than mercury, water will be lifted by air pressure significantly higher up a tube than the same volume of mercury.
To learn more about barometers please visit-
https://brainly.com/question/2856885
#SPJ9
Please please help me it’s due
Your friend has to plan an experiment for a science fair. He asks for your help. His topic is “The Strongest Cloth for Backpacks.” You test the wear of different types of cloth.
Define the independent variable, dependent variable, and control group.
Dependent variable - backpack produced
Independent variable - types of cloth
Control group - backpack without cloth.
What is an experiment?In an experiment, you have the dependent and the independent variable. The independent variable is the variable that we have to change in the experiment. The independent variable is the variable that changes as we change the values in of the independent variable.
Now, we can see that the experiment is about testing which type of cloth is best for backpacks. The independent variable in this case has to be the types of cloth while the dependent variable is the backpack produced. The control group is the backpack without cloth.
Learn ore about experiment:https://brainly.com/question/11256472
#SPJ1
3 waves are shown with a line through their center. The bottom of the first wave is labeled C. A bracket labeled D connects the bottom of the second and third waves. A line from the center to the top of the first wave is labeled A. The line leading to the top is labeled B.
Label the parts of this wave.
A:
B:
C:
D
A – This is the crest, the higher point of the wave
B – This is the amplitude of the wave. It is the point of maximum displacement
C – This is the trough of the wave
D – This is the wavelength of the wave.
What is a wave?A wave is a disturbance, along a medium that transfers energy. We know that a wave is a progressive wave if it moves from one point to another. There are several ways by which we could classify waves.
Waves could be classified as mechanical waves or as electromagnetic waves or as stationary waves and travelling waves or even as transverse waves and longitudinal waves.
In any case, the wave that we have in this image is a travelling wave and we need to obtain the parts of the wave as has been shown in the image that is attached here.
Let us identify the parts of the wave as shown;
A – This is the crest, the higher point of the wave
B – This is the amplitude of the wave. It is the point of maximum displacement
C – This is the trough of the wave
D – This is the wavelength of the wave.
Learn more about waves: https://brainly.com/question/19834734
#SPJ1
a liquid when poured into a graduated cylinder is found to weigh 10 n when occupying a volume of 450 ml (milliliters). determine its specific weight, density, and specific gravity.
The liquid poured into the graduated cylinder has a specific weight, density, and specific gravity of 22,222.22 N/m3, 2,265.26 kg/m3, and 2.26526, respectively.
Given: weight = 10 N and volume = 450 mL or 0.450 L
The specific weight of a substance is defined as its weight per unit volume or density of a substance multiplied to the acceleration of gravity. To obtain a specific weight with units of N/m3, we will be converting the volume from L to m3.
Specific weight = 10 N / 0.450 L = 22.22 N/L
Specific weight = (22.22 N/L) * (1000 L/ 1 m3) = 22,222.22 N/m3
The density can be determined by dividing specific weight by the acceleration of gravity.
Density = Specific Weight / gravity
Density = 22,222.22 N/m3 / 9.81 m/s2
Density = 2,265.26 kg/m3
Specific gravity is a dimensionless quantity of the ratio of the density of a substance to the density of water. The density of water that will be used is 1000 kg/m3.
Specific gravity = Density of substance / Density of water
Specific gravity = 2,265.26 kg/m3 / 1000 kg/m3
Specific gravity = 2.26526
To learn more about specific weight, density, and specific gravity, please refer to https://brainly.com/question/22099107.
#SPJ4
What is the coordination number for atoms that pack within the diamond cubic crystal structure?.
Coordination numbers are defined for the crystalline structures that tell about the numbers of atoms bonded to the central atom. The coordination number of a diamond is 4.
What is a coordination number?A coordination number has been defining the number of the ions, atoms, and molecules that are bonded to the central atom of the crystalline compound or a complex.
The diamond has 8 carbon atoms in its one unit and its coordination number is 4 as its lattice type is face-centered cubic that has carbons at the corners and face center of the structure. One carbon contributes 1/8 hence and the faces center contributes 1/2.
Therefore, the diamond has a coordination number of 4.
Learn more about coordination numbers, here:
https://brainly.com/question/27289242
#SPJ4
Which term or terms can be used to describe this mobel element compound or molecule
The term that can be used to describe this model element compound or molecule is compound. The correct option is b, compound.
What are compounds?Chemical Compounds are substances that are made by joining two or more chemical elements or substances. Compounds are always made of two or more elements.
The picture is given of ammonia, which is made up of nitrogen and hydrogen. The formula of ammonia is NH₃. The compounds are made up of the joining of molecules that are the smallest unit of these compounds.
Thus, the term that will use is compound. The correct option is b.
To learn more about compounds, refer to the link:
https://brainly.com/question/14117795
#SPJ4
The missing image is added below:
How do you solve this?? I will give brainliest for the right answer.
Wavelength of (nm) of photon emitted is 438nm
Wavelength is the distance between identical points means adjacent crest in the adjacent cycles of a waveform signal propagated in space or along a wire
Here in the given data is photon emitted when electron drop at 7th orbital means n = 7 and n = 1 for hydrogen atom and redberg constant is also given = 1.097×10⁷m⁻¹
we have to find wavelength = ?
Expression of wavelength of radiation is
1/λ = R (1/n₁² - 1/n₂²)
1/λ = 109677×(1/7²- 1/1²)
1/λ = 109677×48/49
λ = 438.69cm = 43869m
λ = 438nm
Know more about wavelength
https://brainly.com/question/14126236
#SPJ1
determine the concentration of a solution that has 3 moles of c6h12o6 dissolved in 9 liters of water.
The concentration of a solution that has 3 moles of c6h12o6 dissolved in 9 liters of water is 0.33M
What is Concentration?Concentration is defined as the ratio of number of moles of solute to the volume of the solution.
Concentration = number of moles of solute/ Volume of solution
What is Mole?It is defined as the ratio of given mass of substance to the molar mass of substance.
Given,
given mole of solution = 3 mol
Volume of the solution = 9L.
C = 3/9
C = 1/3
C = 0.33M
Thus, we calculated that the concentration of a solution that has 3 moles of c6h12o6 dissolved in 9 liters of water is 0.33M.
learn more about Concentration or Molarity:
https://brainly.com/question/19517011
#SPJ4
Perform the following calculations and express the answers in
scientific notation.
a. 4.2 x 104 kg + 7.9 x 10³ kg
b. (5.23 x 106 um) (7.1 x 10-² μm)
c. 5.44 x 107 g + 8.1 x 104 mol
d. 8.40 x 105 km - 3.1 x 105 km
The answer of the calculations above in scientific notation are a=8.3 ×10³, b= 3.9 × 10^¹um, c= 1.4 × 10³gmol, d= 5.6× 10²km
Calculation to expressionsIn calculation of various expressions, the results can be expressed in a scientific notation which is a way to compress cumbersome figures.
(4.2 x 104 kg) + (7.9 x 10³ kg)4.2 × 104 = 436.8
7.9 × 10³ = 7900
436.8 + 7900 = 8,336.8
The scientific notation= 8.3 ×10³kg
(5.23 x 106 um) (7.1 x 10-² μm)5.23 x 106 um = 554.38um
554.38 × 7.1 = 3,936.1
3,936.1 × 10^-²
3.9 × 10³ × 10^-²= 3.9 × 10^¹um
The scientific notation= 3.9 × 10^¹um
5.44 x 107 g + 8.1 x 104 mol5.44 x 107 g = 582.08g
8.1 x 104 mol = 842.4 mol
582.08g+ 842.4 mol = 1,424.48
The scientific notation = 1.4 × 10³gmol
(8.40 x 105 km) - (3.1 x 105 km)8.40 x 105 km = 882km
3.1 × 105 = 325.5km
882km - 325.5km = 556.5
The scientific notation = 5.6× 10²km
Learn more about scientific notation here:
https://brainly.com/question/27862246
#SPJ1
How many protons, neutrons, and electrons are replaced in Zr
Answer:
protons 16 elecrons 16
Explanation:
this is because we say that the number of protons is equal to the number of elecrons in a give Element.
classify each of the following amino acids as nonpolar, polar uncharged, polar charged acidic or polar charged basic. justify your classification.
20 standard amino acids are available. Based on the structure and properties of the side chains, these amino acids can be divided into seven classes.
1. Alkyl groups
2. Sulfur-containing
3. Alcohols
4. Acids
5. Bases
6. Aromatics
7. Amides
According to the makeup of their side chains, amino acids are categorised chemically. One helpful classification of amino acids separates them into two groups: polar (or hydrophilic) and nonpolar (or hydrophobic) amino acids. The polar amino acids have side chains that interact with water, whereas the nonpolar amino acids do not.a) Basic (contains a guanidinium group as the side chain)
b. Neutral (contains an alkyl side group)
c. Acidic (contains a carboxylic acid side chain)
d. Polar (contains an amide side chain)
e. Polar (contains a phenol side chain)
f. Non-polar (contains a benzene side chain)
g. Neutral (contains H as the side chain)
Learn more about amino acids here:
https://brainly.com/question/2526971
#SPJ4
The Complete question is mentioned below:
Classify the following amino acids as nonpolar, polar but neutral, acidic, or basic.
(a) Arginine
(b) Leucine
(c) Glutamic acid
(d) Asparagine
(e) Tyrosine
(f) Phenylalanine
(g) Glycine
what happen when chemical reaction takes place between an acid and base
Answer:
When an acid reacts with a base, they undergo neutralization and their opposite pH levels cancel each other out. This happens through the double displacement of ions or, put simply, the ions switch partners.
Explanation:
When an acid and a base are placed together, they react to neutralize the acid and base properties, producing a salt. The H(+) cation of the acid combines with the OH(-) anion of the base to form water. The compound formed by the cation of the base and the anion of the acid is called a salt.
An example of neutralization reaction is: HCL + NaOH ⇆ NaCl +
acid + base ⟶ water + salt.
HCl(aq) + KOH(aq) ⟶ H 2O(ℓ) + KCl(aq)
2 HCl(aq) + Mg(OH) 2(aq) ⟶ 2 H 2O(ℓ) + MgCl 2(aq)
HCl(aq) + NH3(aq) ⟶ NH4Cl(aq)
Answer:
neutralize one another and produce salts
Explanation:
When mixed, acids and bases neutralize one another and produce salts, substances with a salty taste and none of the characteristic properties of either acids or bases.
18. Calculate the mass of a liquid with a density of 2.5 g/mL and a volume of 15 mL
Answer:
1 Answer. fruity · Stefan V. The answer is 2.5 g/cm3 .
Explanation:
True or False: The periodic table has changed very little since it was originally developed by Mendeleev and Meyer.
The periodic table has changed very little since it was originally developed by Mendeleev and Meyer is referred to as a false statement.
What is a Periodic table?
This is defined as the arrangement of elements based on their atomic number in a tabular form. It consists of 18 vertical columns which re referred to as groups and seven horizontal rows called period.
Henry Moseley in 1913 organized Mendeleev's periodic table based on physical properties.This took into consideration their atomic number rather than atomic mass and other missing elements.
This is the periodic table which is used currently and therefore hasn't changed much which is why false was chosen.
Read more about Periodic table here https://brainly.com/question/15987580
#SPJ1
Positively charged particles of radiation emitted from the decay of radioactive substances are known as.
Answer:
Alpha radiation/ alpha decay