Atomic Structure and Isotopes

Question 1

What is in the nucleus of an atom?

Answer 1

Protons and neutrons

Question 2

Where are electrons in an atom?

Answer 2

In shells outside the nucleus

Question 3

What is the relative mass and relative charge of a proton, neutron and electron.

Answer 3

Particle Relative mass Relative charge
Proton 1 +1
Neutron 1 0
Electron Almost zero –1

Question 4

Fill in the gaps: The number of …..-ons in an atom is always the same as the number of ……-ons, so atoms are electrically ………… overall.

Answer 4

The number of electrons in an atom is always the same as the number of protons, so atoms are electrically neutral overall.

Question 5

What do atoms form when they lose or gain electrons?

Answer 5

Charged particles called ions.

Question 6

If an atom loses an electron, what does it become?

Answer 6

A positively charged ion, because there are more protons than electrons.

Question 7

If an atom gains an electron, what does it become?

Answer 7

A negatively charged ion, because there are more electrons than protons.

Question 8

What is the atomic number of an atom?

Answer 8

The number of protons it contains. Also the number of electrons it contains.

Question 9

What is the mass number of an atom?

Answer 9

The total number of protons and neutrons it contains. It is always the bigger number on the periodic table.

Question 10

What is an isotope?

Answer 10

Isotopes are the atoms of an element with different numbers of neutrons. They have the same proton number, but different mass numbers.