Question

How many elements is copper(II)hydroxide composed of? How many atoms?

Answer 1

Hint: The elements in a compound are the substituents which are used to compose the compound in molecular form. The number of atoms is the total number of individual elementary particles in a molecule.

Complete step by step answer:
The elements are referred to as the fundamental particles which are combined to constitute the matter. The elements are called fundamental particles as they are not further decomposed to smaller substances. The elements are arranged in increasing order of their atomic number or number of protons in the periodic table.
In this regard the atoms are the smallest unit of matter which is responsible for the characteristic properties of the matter. The atoms are considered as the basic building blocks of the matter.
Thus an element is the simplest form of any substance and an atom is the smallest unit of a particular element. Atoms are subdivided into subatomic particles called electrons, protons and neutrons. Elements are mixed with the help of chemical reaction to generate compounds or molecules.
The compound given is copper(II)hydroxide. The copper is in \[ + 2\] oxidation state. Thus the oxidation state of copper indicates that the two positive charges are balanced by the two negative charges. The hydroxide ion contains a unit negative charge. Thus two hydroxide ions are required to neutralize the charge of copper ions to make the molecule neutral.
Thus the formula of copper(II)hydroxide is \[Cu{\left( {OH} \right)_2}\]. The formula of copper hydroxide indicates that three elements are present in the formula of copper hydroxide which are copper, oxygen and hydrogen.
The formula of copper hydroxide also indicates that one copper atom and two atoms each of oxygen and hydrogen atom is used to compose the molecules. Thus a total of five atoms is present in copper(II)hydroxide.

Note: In order to determine the number of atoms and elements in a molecule at first we need a balanced chemical formula. The charge of the cations and anions must neutralize to obtain a neutral and stable molecule.