Metals and Non-Metals

Chemical elements can be classified as metals or non-metals based on their properties

MetalsNon-metals
Good conductors of electricity and heatPoor conductors of electricity and heat
Malleable (can be hammered or rolled without breaking)Brittle and fragile in solid state
Ductile (can be stretched into fine wires without losing integrity)Cannot deform without breaking
High melting and boiling pointsLow melting and boiling points

We can know which elements are metallic or not with a simple look at the periodic table.

Metals are located on the left and in the centre of the periodic table, while non-metals are primarily on the right.

A periodic table highlighting metals in yellow and non-metals in blue. Hydrogen, positioned on the left, above the metals, is highlighted in light blue. The table is arranged by increasing atomic number from left to right and top to bottom. The table includes the symbols of the elements, with the metals occupying the majority of the table, and non-metals grouped primarily on the right side and along the diagonal from boron to astatine. Arrows indicate the direction of periods from top to bottom and groups from left to right.

Variation in Properties

Not all metals necessarily have all the characteristics described in the metals and non-metals comparison table above.

As we move from left to right across a period (row), metallic characteristics tend to decrease, and non-metallic characteristics tend to increase. Similarly, moving up a group (column), metallic characteristics decrease, and non-metallic characteristics increase. Therefore, an element positioned lower and further to the left on the periodic table will have more metallic characteristics, and vice versa.

For example, calcium (Ca) has more metallic characteristics than gallium (Ga), and oxygen (O) has more non-metallic characteristics than selenium (Se).

Metalloids

Elements near the border between metals and non-metals on the periodic table are sometimes called metalloids (or semimetals). They possess properties of both metals and non-metals.

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