iGCSE Topic 1c Atomic Structure DOUBLE REVISION MCT

The mass number is the total number of protons and neutrons in the nucleus of an atom.

An atom is the smallest part of an element that can still be recognized as that element.

A neutron is a subatomic particle found in the nucleus of an atom, with no electric charge.

A Helium atom has 2 protons.

The atomic number is the number of protons in the nucleus of an atom, which determines the element's identity.

A proton has a positive charge.

An electron has a negative charge.

The nucleus is the central part of an atom, containing protons and neutrons.

An atom is a single unit of an element, while a molecule is a group of two or more atoms bonded together.

Electrons are responsible for chemical bonding and reactions, as they occupy energy levels around the nucleus.