Class 9 Practice Level 2 – Set 2 – Structure of the Atom

Total questions: 25

An element has an atomic number of 11. How many electrons are in its outer shell?

Topic: Atomic Structure

None

Which isotope of hydrogen has one proton and one neutron?

Topic: Isotopes

Protium

Deuterium

Tritium

Hydrogen-4

None

The atomic number of an element is 12. How many electrons are in its second shell?

Topic: Electron Configuration

None

Which model of the atom introduced the concept of quantized energy levels?

Topic: Bohr’s Model

Dalton's model

Thomson's model

Rutherford's model

Bohr's model

None

How many protons are there in an atom of an element with atomic number 23?

Topic: Atomic Number

None

If an element has 15 protons and 16 neutrons, what is its mass number?

Topic: Neutron Charge

None

An atom of chlorine (atomic number 17) has how many electrons in its third shell?

Topic: Electron Configuration

None

Which pair of elements have the same number of protons but different numbers of neutrons?

Topic: Isotopes

$ \displaystyle {^{{12}}C\text{ }an{{d}^{{14}}}C}$

$ \displaystyle {^{{12}}C\text{ }an{{d}^{{14}}}N}$

$\displaystyle {^{{14}}N\text{ }an{{d}^{{14}}}O}$

$ \displaystyle {^{{13}}C\text{ }an{{d}^{{14}}}N}$

None

In which part of the atom is the majority of its mass concentrated?

Topic: Atomic Structure

Electron cloud

Nucleus

Valence shell

First shell

None

10.

Which atomic model is also known as the "plum pudding" model?

Topic: Atomic Models

Dalton's model

Thomson's model

Rutherford's model

Bohr's model

None

11.

The atomic number of an element is 20. How many electrons are in its outermost shell?

Topic: Electron Configuration

None

12.

If an element has 10 protons and 10 neutrons, what is its mass number?

Topic: Neutron Charge

None

13.

How many electrons are in the third shell of an atom with atomic number 15?

Topic: Electron Configuration

None

14.

Which scientist proposed that electrons move in fixed orbits around the nucleus?

Topic: Atomic Structure

John Dalton

J.J. Thomson

Ernest Rutherford

Niels Bohr

None

15.

Which of the following statements correctly describes the concept of atomic number?

Topic: Atomic Structure

The number of neutrons in the nucleus of an atom.

The total number of protons and neutrons in an atom.

The number of protons in the nucleus of an atom.

The number of electrons in the outermost shell of an atom.

None

16.

How many electrons are in the 3rd shell (M-shell) of an atom with atomic number 15?

Topic: Electron Configuration

None

17.

An element has an atomic number of 12 and a mass number of 24. How many neutrons does it have?

Topic: Neutron Calculation

None

18.

Which of the following pairs represents isotopes of the same element?

Topic: Isotopes

$ \displaystyle {}^{{12}}\text{C}$ and $ \displaystyle {}^{{13}}\text{N}$

$ \displaystyle {}^{{14}}\text{C}$ and $ \displaystyle {}^{{14}}\text{N}$

$ \displaystyle {}^{{12}}\text{C}$ and $ \displaystyle {}^{{14}}\text{C}$

$ \displaystyle {}^{{13}}\text{C}$ and $ \displaystyle {}^{{14}}\text{O}$

None

19.

Who proposed the quantum mechanical model of the atom?

Topic: Atomic Models

J.J. Thomson

Ernest Rutherford

Niels Bohr

Erwin Schrödinger

None

20.

Calculate the number of unpaired electrons in an atom with atomic number 24.

Topic: Electron Configuration

None

21.

Which of the following elements has the highest first ionization energy?

Topic: Ionization Energy

Sodium

Magnesium

Aluminium

Silicon

None

22.

Which of the following electron configurations represents an excited state of an atom?

Topic: Electron Configuration

$ \displaystyle \text{1}{{\text{s}}^{2}}\text{2}{{\text{s}}^{2}}\text{2}{{\text{p}}^{6}}$

$ \displaystyle \text{1}{{\text{s}}^{2}}\text{2}{{\text{s}}^{2}}\text{2}{{\text{p}}^{5}}3{{\text{s}}^{1}}$

$ \displaystyle \text{1}{{\text{s}}^{2}}\text{2}{{\text{s}}^{2}}\text{2}{{\text{p}}^{6}}3{{\text{s}}^{2}}3{{\text{p}}^{1}}$

$ \displaystyle \text{1}{{\text{s}}^{2}}\text{2}{{\text{s}}^{2}}\text{2}{{\text{p}}^{6}}3{{\text{s}}^{2}}3{{\text{p}}^{6}}$

None

23.

Which of the following elements experiences the greatest effective nuclear charge on its valence electrons?

Topic: Effective Nuclear Charge

Sodium

Magnesium

Aluminium

Silicon

None

24.

An atom has 11 protons, 12 neutrons, and 11 electrons. What is its atomic mass?

Topic: Atomic Mass

11 amu

22 amu

23 amu

34 amu

None

25.

The isotope deuterium of hydrogen has:

Topic: Isotopes

One electron and two neutron

One neutrons and two protons

One proton and one neutron

No neutrons and one proton

None

1 out of 25

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Class 9 Practice Level 2 – Set 2 – Structure of the Atom

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