Forming ions for ionic bonding | Starter Quiz | Oak National Academy

Which of the following subatomic particles are found in the nucleus of an atom?

• proton

• neutron

• electron

• ion

Answer explanation

The nucleus of most atoms contain protons and neutrons. Electrons are found in shells around the nucleus.

Match the following subatomic particles to the correct charge.

• electron

• 1+

• neutron

• 0

• proton

• 1–

Answer explanation

The nucleus of an atom is positively charged as it contains protons (which are positively charged) and neutrons (which have no charge). However, an atom is neutral overall as it has negatively charged electrons orbiting the nucleus in its shell.

Why do atoms have no overall charge?

• They contain the same number of protons as electrons.

• They contain the same number of protons as neutrons.

• They contain the same number of neutrons as electrons.

Answer explanation

Atoms contain equal numbers of positively charged protons and negatively charged electrons. If the number of protons equals the number of electrons then the charges cancel out and there will be no overall charge.

Oxygen is in Group 6 of the periodic table. How many electrons does an oxygen atom have in its outer shell?

Answer explanation

An oxygen atom has two electrons in its first shell and six electrons in its outer shell, making a total of eight electrons.

A potassium atom has 19 electrons in total. How many electrons are there in the outer shell of a potassium atom?

Answer explanation

The 19 electrons are divided into the electron shells in the following configuration: 2,8,8,1. This means a potassium atom has four electron shells and there is one electron in the outer shell.

Sulfur is in Group 6, Period 3 on the periodic table. What does this tell you about sulfur?

• A sulfur atom has six electrons in its outer shell.

• A sulfur atom has three electrons in its outer shell.

• A sulfur atom has three shells of electrons.

• A sulfur atom has six shells of electrons.

Answer explanation

A sulfur atom has three shells of electrons and six electrons in its outer shell. The electron configuration for a sulfur atom is therefore: 2,8,6.