APCE Atomic Structure & Periodicity

Question 1

What is the atomic number of an element?

Accepted Answer

The number of protons in the nucleus.

Answer

The number of electrons.

Answer

The number of neutrons.

Answer

The total number of subatomic particles in an atom.

Question 2

What does the periodic table’s periodicity refer to?

Accepted Answer

The repetition of chemical properties in groups of elements.

Answer

The arrangement of elements in order of increasing atomic mass.

Answer

The random arrangement of elements.

Answer

The number of protons in an atom.

Question 3

What is the electron configuration of oxygen (O)?

Accepted Answer

1s² 2s² 2p⁴.

Answer

1s² 2s² 2p⁶.

Answer

1s² 2s² 3p⁶.

Answer

1s² 2p⁶.

Question 4

How does atomic radius change across a period in the periodic table?

Accepted Answer

It decreases across a period.

Answer

It increases across a period.

Answer

It stays the same across a period.

Answer

It fluctuates without a clear trend.

Question 5

What is ionization energy?

Accepted Answer

The energy required to remove an electron from an atom or ion.

Answer

The energy required to add an electron.

Answer

The energy required to break a chemical bond.

Answer

The energy released when an electron is added.

Question 6

What does electronegativity refer to?

Accepted Answer

An atom's ability to attract electrons in a bond.

Answer

The number of protons in an atom.

Answer

The number of neutrons in an atom.

Answer

The energy required to remove an electron.

Question 7

What is the periodic trend for electron affinity?

Accepted Answer

Electron affinity increases across a period.

Answer

Electron affinity decreases across a period.

Answer

Electron affinity stays the same across a period.

Answer

Electron affinity decreases down a group.

Question 8

What is the shielding effect in atomic structure?

Accepted Answer

The blocking of nuclear attraction by inner electrons.

Answer

The attraction of the nucleus for the electrons.

Answer

The repulsion of electrons in the same energy level.

Answer

The energy required to remove an electron.

Question 9

What is the role of quantum numbers in describing atomic structure?

Accepted Answer

To describe the properties of atomic orbitals and electrons.

Answer

To determine the atomic number.

Answer

To determine the number of neutrons.

Answer

To calculate the molecular weight.