class+notes+V

__Chemical reaction__ – Any change that involves the formation of a new substance. A chemical reaction has reactants and products.

__Law of conservation of matter__ – matter (atoms) cannot be created or destroyed only rearranged

Coefficient – number in front. Tells you how many molecules you have. Subscript – Small number below that tells you how many atoms of each element

Atom – the smallest particle of an element that retains the properties of that element

Molecule – the smallest particle of a compound that retains the properties of that compound

Ion – A charged atom. The number of protons and electrons differ (can be positive or negative)

Isotope – The number of protons and neutrons differ (does not affect charge)

Things that are unrealistic about the Bohr model of atoms

1. Electrons not on rings 2. Electrons are always moving 3. Electrons would be much further from nucleus 4. Electrons are much much smaller than protons and neutrons 5. Too simplified. There are other parts! 6. Atoms are 3-Dimentional

Valence electrons – electrons in the outermost energy level

Octet rule – atoms gain, lose or share to get 8 electrons in their outer shell (stable) (2 for H, He, Li, Be, due to their size)


 * 2,8,8****

Ionic Bond – bonding that involves a transfer of electrons. Always between a metal and a non-metal.

Covalent bond – bonding that involves a sharing of electrons. Always between a non-metal and a non-metal.