most abundant elements Cut along the dotted lines then fold Anything that has weight and takes up space Matter Four most abundant elements Oxygen Carbon Hydrogen Nitrogen These are created when atoms can combine with atoms like themselves or with other atoms by forming attractions. Chemical bonds

An element from the periodic table An element from the periodic table Cut along the dotted lines then fold Parts of an atom Parts of an atom PROTON NEUTRON ELECTRON NUCLEUS An element from the periodic table An element from the periodic table Li 3 6.941 Lithium Li 3 6.941 Lithium 1 Atomic number (also # of protons) (also # of electrons) 2 Atomic weight This is formed when two or more atoms of the same element bond Molecule

Maximum number of electrons in the first three inner shells of an atom Cut along the dotted lines then fold This is formed when two or more atoms of different elements bond Compound Maximum number of electrons in the first three inner shells of an atom First shell: 2 Second shell: 8 Third shell: 8 Helium is more stable because its outermost shell is filled. Which element is more stable? Why?

Ionic bond Covalent bond Polar covalent bond Cut along the dotted lines then fold Ionic bond Formed when atoms gain or lose electrons Covalent bond Formed when atoms share electrons This is formed when a polar molecule has an equal number of protons and electrons, but one end of the molecule has more than its share of electrons, becoming slightly negative, while the other end of the molecule has less than its share, becoming slightly positive. Polar covalent bond

Hydrogen bond Ionic bond Covalent bond Cut along the dotted lines then fold Formed between an electropositive atom and an eletronegative atom Hydrogen bond What type of bond is this? Ionic bond What type of bond is this? H2 Covalent bond

Molecular formula Hydrogen bond Polar covalent bond H2O H O Cut along the dotted lines then fold What type of bond is this? Hydrogen bond electropositive electronegative H O What type of bond is this? Polar covalent bond The symbols of the elements in the molecule together with numbers to indicate how many atoms of each element are present. Example: Molecular formula H2O