Chemistry 2A

Two types of chemical compounds: o Ionic compounds - composed of positively and negatively charged ions held together by strong electrostatic forces ▪ Examples: NaCl, CaCO3 o Covalent compounds - composed of individual molecules, discrete groups of atoms that share electrons. ▪ Examples: H2O and CH4

Pure substances - elements, covalent compounds, and ionic compounds ● Mixture - two or more pure substances o Heterogeneous mixture - does not have a uniform composition throughout the sample o Homogeneous mixture - has a uniform composition throughout the sample