Atomic Number and Mass Number

Q.

What is the number of atoms present in 4.25 grams of $N{H}_3$ is approximately??

Q.

What is the ground-state electron configuration for $\mathrm{Zn}$?

Q.

The total mass of 1mole electron is (mass of 1e-=9.1*10^-28g)

Q.

The electron configuration for magnesium is $1{\mathrm{s}}^{2}2{\mathrm{s}}^{2}2{\mathrm{p}}^{6}3{\mathrm{s}}^2$. What is the distribution of electrons in the electron shells of a magnesium atom?

Q.

What is the charge of a proton in coulombs?

Q.

The minimum number of moles of $O_2$ required for complete combustion of $1$ mole of propane and $2$moles of butane is

Q. The number of neutrons in dipositive zinc ion with mass number 70 is:

1. 36
2. 38
3. 40
4. 34

Q.

The element potassium has an atomic number 19 and a mass number is 39. Give the number of electrons, protons, and neutrons in it. Give the electronic configuration in different energy shells. Mention its valency.

Q. Difference between molecular mass and molar mass

Q.

What is the electronic configuration of Barium?

Q. Suppose the elements X and Y combine to form two compounds $X{Y}_2$ and $X_3{Y}_2$. When 0.1 mole of $X{Y}_2$ weighs 10 g and 0.05 mole of $X_3{Y}_2$ weighs 9 g, the atomic weights of X and Y are

1. 20, 30
2. 30, 20
3. 40, 30
4. 60, 40

Q.

An element with mass number 81 contains 31.7% more neutrons as compared to protons. Assign the atomic symbol.

Q. Which of the following pair(s) is/are isodiaphers?

1. ${}_6^{14}Cand{}_{11}^{23}Na$
2. ${}_{12}^{24}Mgand{}_{11}^{23}Na$
3. ${}_2^{4}Heand{}_8^{15}O$
4. ${}_9^{19}Fand{}_6^{13}C$

Q.

Which of the following has maximum number of atoms?

1. $18\mathrm{g}$ of ${\mathrm{H}}_2\mathrm{O}$

2. $18\mathrm{g}$ of ${\mathrm{O}}_2$

3. $18\mathrm{g}$ of ${\mathrm{CO}}_2$

4. $18\mathrm{g}$ of ${\mathrm{CH}}_4$

Q.

A nitrogen atom contains 7 protons, 7 electrons and 7 neutrons. why is it that the atomic mass of nitrogen is 14 and not 21?

Q.

Use the data given in the following table to calculate the molar mass of naturally occurring argon isotopes:

Isotope	Isotopic molar mass	Abundance
36Ar	35.96755 gmol–1	0.337%
38Ar	37.96272 gmol–1	0.063%
40Ar	39.9624 gmol–1	99.600%

Q. What is the total volume of the particles present in a body centered unit cell?

1. $8\pi r^3$
2. $\frac{8}{3}\pi r^3$
3. $\frac{16}{3}\pi r^3$
4. $\frac{32}{3}\pi r^3$

Q.

What is the charge of 96 amu of S2-

Q.

An ion with mass number 37 possesses one unit of negative charge. If the ion contains 11.1% more neutrons than the electrons, find the symbol of the ion.

Q. Calculate the mole fraction of ethylene glycol $C_2{H}_6{O}_2$ in a solution containing $20\%\text{of}{C}_2{H}_6{O}_2$ by mass.

Q.

How many neutrons are present in the Hydrogen atom.

Q.

Which of the following sample(s) must have an average molar mass greater than that of a mixture of ${\mathrm{N}}_2$ and ${\mathrm{CO}}_2$?

1. Pure ${\mathrm{O}}_3$

2. Pure $\mathrm{Ne}$

3. Mixture of ${\mathrm{SO}}_2$ and ${\mathrm{SO}}_3$

4. Mixture of ${\mathrm{CH}}_4$ and ${\mathrm{SO}}_3$

Q.

The gram molecular mass of oxygen is

1. 16g

2. 32g

3. 64g

4. 48g

Q.

The electronic configuration of gadolinium atomic no $64$ is

1. $\left[\text{Xe}\right]4f^{3}5d^{5}6s^2$

2. $\left[\text{Xe}\right]4f^{6}5d^{2}6s^2$

3. $\left[\text{Xe}\right]4f^{8}5d^{9}6s^2$

4. $\left[\text{Xe}\right]4f^{7}5d^{1}6s^2$

Q.

If number of electrons in an atom is 8 and number of protons are also 8, then (i) what is the atomic number of the atom? And (ii) what is the charge on the atom?

Q.

Calculate the percentage of nitrogen in ${\mathrm{NH}}_3$ (Atomic Mass Of N =14 An H=1 Amu).

Q.

Estimate the molar mass of Aluminium.

Q. An element has a bcc structure having unit cells $12.08\times {10}^{23}$. Find the total number of atoms in these unit cells.

1. $24.16\times {10}^{23}$
2. $12.08\times {10}^{23}$
3. $36.24\times {10}^{23}$
4. $6.02\times {10}^{23}$

Q. If the number of protons in $X^{2-}$ is 16, then the number of electrons in $X^{2+}$ will be:

1. 14
2. 16
3. 18
4. Cannot be determined

Q. 300 ml 0.1 M HCl and 200 ml of 0.03 M $H_{2}S{O}_4$ are mixed. Calculate the normality of the resulting mixture.

1. 0.084 N
2. 0.84 N
3. 2.04 N
4. 2.84 N