Unit 2 MCQ Revision Test

What does the atomic number of an element represent?

• The number of neutrons in the atom

• The number of electrons in the nucleus

• The number of protons in the atom

• The total number of protons and neutrons

What happens to the mass of atoms as you move from left to right in the periodic table?

• It decreases

• It increases

• It stays the same

• It fluctuates randomly

What is the charge of a neutron?

• Positive

• Negative

• Neutral (no charge)

• It depends on the element

Why does an atom have no overall charge?

• Because it contains equal numbers of protons and electrons

• Because neutrons cancel out the charge

• Because electrons have no charge

• Because protons and neutrons have the same charge

If lithium has an atomic number of 3 and a mass number of 7, how many neutrons does it have?

• 3

• 4

• 7

• 10

What is the term for the measure of mass per unit volume of a substance?

• Weight

• Density

• Mass number

• Atomic weight

Which of the following scientists developed the model where electrons orbit the nucleus in shells?

• J.J. Thomson

• Ernest Rutherford

• Niels Bohr

• Isaac Newton

According to Bohr’s model, what holds electrons in their shells?

How many electrons can the first electron shell hold?

• 1

• 2

• 4

• 8

What is the correct electronic configuration for a boron atom?

• 2.3

• 3.2

• 2.8

• 4.1