Periodic Table (The Periodic Table)

As you go down group 1

Softness increases, density increases, melting point decreases, reactivity increases.

Group 1

Alkali metals.

Atoms with in the same group

React in the same way

Group 17

The halogens

Group 18

Noble gases

Group 2

Alkaline earth metals

Groups 3-12

transition metals

metalloids

Found along the 'staircase'. Have properties of both metals and nonmetals

nonmetals

brittle , dull, poor conductors of heat and electricity, and have much lower melting and boiling points

Proton

Positively charged particle in the nucleus of an atom

Neutron

A subatomic particle that has no charge and that is found in the nucleus of an atom

Electron

A tiny, negatively charged particle that moves around the nucleus of an atom.

Atomic Number

The number of protons in the nucleus of an atom of an element

Mass Number

The total number of protons and neutrons in an atom's nucleus

Periodic table

A chart of all chemical elements currently known, organized by their properties.

Element

pure substance that consists entirely of one type of atom

atom

the smallest unit of an element that maintains the properties of that element

group

oxygen and sulfur are in the same ______

periods

horizontal rows on the periodic table are called ____________

groups

vertical columns on the periodic table are called __________