Atomic Mass

Q.

Define one atomic mass unit (a.m.u.).

Q.

What are the drawbacks of the law of Dobereiner Triad ?

Q.

What is gram atomic mass? Give one example

Q.

The letter of the English alphabet that does not appear in any of the symbols of elements in the periodic table is __________

Q.

Is 2Na different from Na₂ ?_{​​​​​}​​​​​

Q.

What are the characteristics of isotopes?

Q.

Relative abundance of isotopes of carbon are as follows:-

Isotopes	Relative abundance	Atomic Mass
C-12	$98.892$	12
C-13	$1.108$	13.00335
C-14	$2\times {10}^{-10}$	14.00317

The average atomic mass of carbon will be:-

1. 16.0056 u

2. 12.001 u

3. 15.001 u

4. 10.001 u

Q.

The atomic number of Unnilunium is?

Q. The electronic configuration of lithium atom is .

1. 2, 1
2. 1, 2
3. 2, 4
4. 2, 3

Q.

1 u or 1 amu (atomic mass unit) is equal to: _______.

1. 

2. 

3. 12g of carbon atoms

4. 16g of oxygen atoms

Q.

The mass number of an atom is equal to the number of ____ in its nucleus.

Q.

Mg has three natural isotopes whose isotopic masses and relative abundances are respectively 23.98 (78.60%), 24.98(10.11%) and 25.98(11.29%). The atomic mass of Mg will be

1. 24.95u

2. 23.95u

3. 23.42u

4. 24.31u

Q.

Hydrogen has three isotopes (A), (B) and (C). If the number of neutron(s) in (A), (B) and (C) respectively, are (x), (y) and (z), the sum of (x), (y) and (z) is:

Q.

What is the mass number of an atom which contains 28 protons, 28 electrons, and 34 neutrons?

1. 28

2. 56

3. 62

4. 90

Q.

What does the abbreviation amu stand for?

1. Atomic mass unit

2. Atomic molecular unit

3. Atomic mole unit

4. Atomic measuring unit

Q.

How do you tell the difference between isotopes?

Q.

The molecular formula of a compound is $C_2{X}_6$. X is unknown. If the mass ratio of C to X is 4:1 in the compound, find X.

1. Helium

2. Sodium

3. Calcium

4. Hydrogen

Q.

We use an atom of _______ as the standard particle for comparing the masses of atoms of other elements.

1. oxygen

2. carbon

3. helium

4. hydrogen

Q.

What is the empirical formula of C₄H₈O₂?

1. CHO

2. C₄H₈O₂

3. C₂H₂O₂

4. C₂H₄O

Q.

A sample of naturally occurring silicon con­sists $\mathrm{Si}-28$ $(27.9769\mathrm{u})$, $\mathrm{Si}-29$ $(28.9765\mathrm{u})$ and $\mathrm{Si}-30$ $(29.9738\mathrm{u})$. If the atomic mass of silicon is $28.0855$ and the natural abundance of $\mathrm{Si}-29$ is $4.67\%$, what are the natural abundances of $\mathrm{Si}-28$ and $\mathrm{Si}-30$?

Q.

Give Latin names for sodium and mercury.

Q. Atomic mass is the total mass of the protons and electrons present in the atom.

1. True
2. False

Q.

How two isotopes of chlorine differ?

Q.

Find the ratio by mass of the combining elements in the compound - $C_2{H}_{5}OH$.

1. Ratio of C: H: O is 8:3:12 respectively.

2. Ratio of C: H: O is 2:6:1respectively.

3. Ratio of C: H: O is 6:2:1 respectively.

4. Ratio of C: H: O is 12:3:8 respectively.

Q.

Which of the following statements is/are incorrect for isotopes of an element:-

1. Isotopes have different chemical properties
   

2. Isotopes have same number of neutrons

3. Isotopes have different number of protons

4. Isotopes have same number of electrons

Q.

An isotope of helium is represented by the symbol ${}_2^{3}He$ How many protons, neutrons and electrons are there in an atom of the isotope?

1. Proton:- 1

   Neutron:- 2

   Electron:- 1

2. Proton:- 1

   Neutron:- 3

   Electron:- 2

3. Proton:- 2

   Neutron:- 1

   Electron:- 2

4. Proton:- 2

   Neutron:- 3

   Electron:- 2

Q. have the same chemical properties, whereas have different chemical properties.

1. Isobars
2. Isotopes
3. Electrons
4. Protons

Q.

The atomic mass of chlorine is 17 u.

1. True

2. False

Q.

The mass number of a nucleus is equal to the number of

1. neutrons it contains

2. electrons it contains

3. nucleons it contains

4. protons it contains

Q. The mass number of an atom is the sum of number of:

1. protons and electrons
2. protons and nucleons
3. protons and neutrons
4. electrons and nucleons