### Chemistry - Atomic Structure and Periodic properties of Elements

#### Question - 1

Given atomic mass of silver = 107.87. The mass of silver atom atom would be

• A 1.79 X 10-24
• B 1.79 X 10-22
• C 1.79 X 10-21
• D 1.79 X 10-20

#### Question - 2

If international atomic mass of magnesium is 24.3, the mass of one atom of magnesium would be

• A 1.66 X 10-24 g
• B 40.34 X 10-24 g
• C 16.6 X 10-24 g
• D 4.03 X 10-24 g

#### Question - 3

Atomic mass of an element is not necessarily a whole number because it contains

• A allotropic forms
• B protons and neutrons
• C indivisible atoms
• D isotopes

#### Question - 4

Carbon occurs as a mixture of $_{ 6 }^{ 12 }C$ and $_{ 6 }^{ 13 }C$. The atomic mass of $_{ 6 }^{ 12 }C$ is exactly 12 amu by definition and the atomic mass of  $_{ 6 }^{ 13 }C$ is 13.003 amu. If the average atomic mass of carbon is 12.001 amu, the atom percent of $_{ 6 }^{ 12 }C$ in natural carbon would be

• A 99.2
• B 98.9
• C 94.6
• D 99.0

#### Question - 5

The line spectrum observed when electrons fall from higher quantum levels to L level is referred to as

• A Balmer series
• B Lyman series
• C Paschen series
• D Brackett series

#### Question - 6

Given the electronic configuration 1s2, 2s2, 2p3 the number of unpaired electyrons in the atom is

• A 0
• B 1
• C 3
• D 7

#### Question - 7

A subshell with l=3, can take up the maximum number of electrons as

• A 10
• B 8
• C 12
• D 14

#### Question - 8

A d-orbital can accomodate electrons up to

• A two
• B ten
• C six
• D fourteen

#### Question - 9

Bohr radius of nth orbit of an atom is given by the expression

• A $\quad r=\frac { { n }^{ 2 }{ h }^{ 2 } }{ 4{ \pi }^{ 2 }mZ{ e }^{ 2 } }$
• B $\quad r=\frac { { n }^{ 2 }{ h }^{ 2 } }{ 4{ \pi }^{ 2 }mZ{ } }$
• C $\quad r=\frac { { n }^{ 2 }{ h }^{ 2 } }{ 4{ \pi }^{ 2 }m{ e }^{ 2 } }$
• D $\quad r=\frac { { n }^{ }{ h }^{ } }{ 4{ \pi }^{ 2 }m{ e }^{ 2 } }$

#### Question - 10

The line spectra are the characteristics of

• A atoms in the excited state
• B atoms in ground state
• C molecules in the excited state
• D molecules in ground state