Science

Atom

Smallest particle of matter.

Element

Pure substance made from only one atom type.

Compound

Pure substance made from two or more different elements, chemically bonded.

Mixture

Two or more pure substances that aren’t chemically bonded.

Pure substance

Sample of matter with definite chemical and physical properties.

Lattice

Substance made from two or more chemically combined atoms, includes at least one metal.

Molecule

Substance made from two or more chemically combined non-metal atoms, discreet units.

Protons

Positive particles found in the nucleus, heaviest part of the atom.

Neutrons

Neutral particles that hold protons together in the nucleus.

Electrons

Negative charge particles that are in constant motion and can be shared or transferred between atoms.

Atomic Number

Number of protons in the nucleus of an atom.

Mass Number

Total number of protons and neutrons in the nucleus of an atom.

Electron Shell

Groups of electrons in different energy levels around an atom's nucleus.

Alkali Metals

Group 1 elements that are non-acidic and react easily with water.

Alkaline Earth Metals

Group 2 metals, less reactive than alkali metals, found naturally in the earth.

Transition Metals

Groups 3 to 12, known for forming ions and compounds, usually hard with high densities.

Halogens

Group 17 reactive non-metals that react with metals to form ionic compounds.

Noble Gases

Group 18 elements, unreactive due to stable valence shells.

Cations

Positively charged ions that lose electrons.

Anions

Negatively charged ions that gain electrons.

Ionic Compounds

Formed when a metal reacts with a non-metal, consisting of metallic cation and non-metallic anion.

Electrostatic Attraction

Attraction between oppositely charged ions in ionic compounds.

Brittleness of Ionic Compounds

Brittleness is due to ions lining up with like charges when force is applied.

Solubility of Ionic Compounds

Ionic compounds dissolve in water due to the attraction between water molecules and ions.

Conductivity in Ionic Compounds

Ionic compounds can conduct electricity when dissolved in water or molten due to free-moving ions.

Metallic Bonding

Cations in a sea of delocalized electrons, enabling conductivity, malleability, and lustrous properties.

Lustrous

Describes the reflective quality of metals due to free-moving electrons.

Malleability

Property that allows metals to be hammered or rolled into thin sheets.

High Melting Point

Characterizes metals requiring large amounts of energy to overcome electrostatic attractions.