Metals and Non-metals

Elements on the periodic table can be broadly divided into metals and non-metals. These two types of elements have different physical and chemical properties.

Where are they on the periodic table?

There is a clear dividing line between metals and non-metals on the periodic table, often shown as a “staircase” starting beneath boron (B).

Metals are found to the left and bottom of the staircase
Non-metals are on the right and top

Some elements that touch the staircase (like silicon) are called metalloids or semi-metals, and they have properties of both.

Physical properties

Property	Metals	Non-Metals
Appearance	Shiny (when polished)	Dull
State at room temp	Solid (except mercury)	Often gases or brittle solids
Malleability	Malleable (can be hammered)	Brittle (break when hit)
Ductility	Ductile (can be drawn into wires)	Not ductile
Conductivity	Good conductors of heat & electricity	Poor conductors (except graphite)
Density	High	Low
Melting/boiling pts	Usually high	Usually low

Chemical properties

Metals:

Tend to lose electrons to form positive ions (cations)
React with oxygen to form basic oxides (e.g. magnesium oxide)

Non-metals:

Tend to gain electrons to form negative ions (anions)
React with oxygen to form acidic oxides (e.g. sulfur dioxide)

💡 Metals aim to lose electrons to achieve a full outer shell, while non-metals aim to gain electrons for the same reason.

Questions

Where are metals found on the periodic table?
What is a common physical property of non-metals?
Do metals usually form positive or negative ions?
What does malleable mean?
Why do metals lose electrons in reactions?

Summary
Metals are shiny, malleable, and good conductors; non-metals are dull and brittle.
Metals form positive ions; non-metals form negative ions.
A staircase line on the periodic table separates metals and non-metals.
Metals are on the left; non-metals are on the right.
Their physical and chemical properties are different due to electron behaviour.