#1

What does an atom look like? What are the sub-atomic particles inside it?

(Talk about protons, neutrons, electrons, etc...)

Atom: The smallest particle that has some subatomic particles.

Subatomic particles: electrons, protons, neutrons

Picture of an atom:

An electron is negatively charged. It has a relative charge of -1 and a relative mass of 1/1840. It's mass is much lighter than than that of a proton and neutron. Electrons are the smallest part of an atom. It is found in the atom's shells. A maximum of 2 electrons is found in the first shell. 8 electrons in the second shell and so on. The 4th shell can contain 18 electrons. The electron is what controls the charge (either positively or negatively) of the atom. An atom lose or gain electron(s) in order to achieve stability.

The nucleus of an atom is made up of the proton and the neutron. The sum of the neutron and proton number is called the atomic mass number. In other words, the nucleon number.

The number of protons in the nucleus of an atom is called the proton number/atomic number. The relative charge of protons is +1 and their relative mass is 1. It's mass is the same of a neutron.

For the neutron, it's relative charge is -1 and it's relative mass is 1. (Mass same as that of proton)