Complete the sentences about the structure of an atom. Use words from the list below:
electrons, negative, neutral, neutrons, positive, protons
An atom has a nucleus with a .................... charge. The nucleus is made up of .................... and .................... .
Look at the information about two isotopes of oxygen:
Isotope 1: 816OIsotope 2: 818O\text{Isotope 1: } {}^{16}_{8}\text{O} \qquad \text{Isotope 2: } {}^{18}_{8}\text{O}Isotope 1: 816OIsotope 2: 818O
Which two statements about the isotopes of oxygen are correct?
The diagram shows an oxygen atom.

Explain why oxygen is in Group 6 of the Periodic Table.
Oxygen is in Group 6 of the Periodic Table. Oxygen is a non-metal.
Why do non-metals form negative ions?
Oxygen reacts with magnesium to form magnesium oxide.
What is the symbol for a magnesium ion?