Question

What is metal oxide?
A. Metal + oxygen
B. Metal + ozone
C. Metal + water
D. Metal + water + oxygen

Answer 1

Metal oxide is a form of crystalline solids that is made up of metal cation and oxide anion. The metal oxides typically react with the acids for the formation of salt and it reacts with water to form bases. It is formed with the combination of metal and oxygen.

Complete answer:
From your chemistry lessons you have learned about the metal oxide and the composition of metal oxide.
Metals oxide is a compound that is formed by the reaction between metal and oxygen. It is a type of chemical compound which is formed between the metals specially the cations such as potassium, lithium, sodium, etc and the oxide anion.
To form metal oxides we require at least two elements as compounds do and in this compound there should be at least one oxygen though they can be one or more than one. Metal oxides generally contain a negative oxygen which have the oxidation state of -2.
Let us take an example of metal oxide to check how metal reacts with oxygen to form metal oxide. We will take the magnesium ion (metal ) which reacts with oxygen to form the magnesium oxide and the reaction is given as:
$2Mg+{{O}_{2}}\to 2MgO$
Therefore, we can say that the metal oxide is the combination of metal + oxygen.

Thus the correct option will be (A).

Note:
You should be aware that metal oxides are always basic in nature. As we have magnesium oxide which is a type of metal oxide is basic in nature and you can check it by adding water to it. When we add water to it it will form $Mg{{(OH)}_{2}}$ which is called magnesium hydroxide and it is a base.