Atoms

• Atoms are the basic building block of an element
• Atomic number is the number of proton in the nucleus of an atom
• Isotopes have different numbers of neutrons but same atomic number
• Atoms contain: Protons, neutrons and electrons.
• Protons are positively charged particles found in the nucleus of an atom
• Electrons are negatively charged particles that are on the shell and orbit around the nucleus of an atom
• Ions are charged particles
• Ions can be positively charged or negatively
• The atomic mass is the sum of protons and neutrons in an atom.
• The nucleus contains proton and neutrons
• Neutrons have no charge and are found in the nucleus of an atom
• A period is a row in the periodic table
• A group is a column in the periodic table
• an element is a substance made from one type of atom
• a compound is 2 or more elements chemically bonded together
• The shells in an atom surround the nucleus
• Atoms have a radius of 0.1nm
• Proton's relative mass is 1
• relative mass of a neutron is 1
• Relative mass of an electron is 1/2000 or 0.005
• Neutrons = Atomic mass - atomic number
• Isotopes are atoms of the same element with a different amount of neutrons
• Plum pudding model: A model of the atom that was proposed by John Dalton in 1803
• The plum pudding model has no nucleus, and is overall positive with electrons inside
• The nuclear model has a nucleus with electrons on the shells
• Maximum electrons on 1st shell is 2
• maximum electrons on 2nd shell is 8
• Losing electrons make the atom positive
• Gaining electrons makes the atom negative
• metal + non metal = ionic bonding
• metal + metal = metallic bonding
• non-metal + non-metal = covalent bonding
• covalent bonds are weak as there's not much energy needed to break them
• ionic bonds are strong because they have high melting points, boiling points and are brittle
• ions are when electrons are transferred, when atoms loose or gain electrons
• positive ions are called cations
• negative ions are called anions