Atoms

• The nucleus is the central part of an atom, containing protons and neutrons.
• Electrons are negatively charged particles that orbit around the nucleus of an atom at different energy levels called shells or electron clouds.
• Atomic number (Z) refers to the number of protons in the nucleus of an atom.
• Mass number (A) represents the total number of protons and neutrons in the nucleus of an atom.
• The basic structure of an atom consists of a central nucleus surrounded by electrons that orbit around the nucleus in shells
• The nucleus of an atom is made up of protons and neutrons, while electrons orbit around the nucleus
• Protons and neutrons have the same mass, which is considered a relative mass of one, while electrons are much smaller with a mass 2000 times smaller
• Protons have a positive charge (one plus), neutrons are neutral (no charge), and electrons have a negative charge (minus one)
• Atoms can lose or gain electrons, leading to the formation of ions which are charged particles
• The atomic number of an element tells us how many protons the atoms of that element have, while the mass number tells us the total number of neutrons and protons in the atom
• Ions are atoms with either positive or negative charges resulting from losing or gaining electrons.