Ch 2 Vocab

Atom

tiny particles of matter

Electron

-1 charge

found outside of nucleus

~0 amu

Proton

+1 charge

found inside nucleus

1 amu

Neutron

0 charge

found inside the nucleus

1 amu

Atomic Number (Z)

equal to the number of protons and electrons in an atom

Mass Number (A)

the sum of all the particles in the nucleus

isotopes

atoms of the same element that have different mass numbers

same number of protons, different number of neutrons

Metals

shiny, lustrous in appearance

solids at room temperature

good conductors of heat electricity

malleable

Nonmetals

can be solid, liquid, or gas

poor conductors of electricity and heat

brittle and dull

lower densities than metals

Alkali Metals

Group 1A

shiny, soft, and low melting point

React rapidly with H₂O

Alkaline Earth Metals

Group 2A

Lustrous, silvery metals

Not as reactive as Alkali Metals

Halogens

Group 7A

Colorful and corrosive nonmetals

found in nature in combination with other elements

Noble Gases

Group 8A

colorless gases

relatively unreactive

Orbitals

3D space around a nucleus where an electron is found