4 What are constituents of an atom ? Calculate formula mass of NaNO3.
Answers
Constituents of an atom are made up of three main particles which are as follows:
- Protons: Positively charged
- Electron: Negatively charged
- Neutron: No charge or neutral
Protons and neutrons are present inside the nucleus of the atom and electrons are present in the orbit of the atom.
Formula mass: The total number of protons and neutrons present in the nucleus of an atom is known as the mass of that atom or mass number. When the different atoms are present in groups then it is known as molecular formula and the mass calculated is the formula mass or molecular weight. It is measured in atomic mass unit ie. u.
The Atomic mass of Na = 23 u
The Atomic mass of N = 14 u
The Atomic mass of O = 16 u
The Atomic mass of O₃ = 16 u x 3 = 48 u
Formula mass of NaNO₃ = Na + N+ O₃ = 23 u + 14 u + 48 u = 85 u
Therefore,
Formula mass of NaNO₃ is 85 u.