Groups
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Periods and groups are used to organize the iconic periodic table into columns and
rows.
Groups, also called families, are the vertical columns.
There are 18 groups
The elements arranged into groups are based on certain characteristics such as
chemical or physical properties.
As you go down a column the atomic radius increase
Reactivity of elements increases down the group as down the group number of shells
increases and thus nuclear pull on the outermost electrons decreases.
Periods
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Each horizontal row of an element is called a period
There are 7 periods
Each period denotes a new energy shell. From hydrogen down to francium the
elements increase in atomic orbitals.
The first element in a period is always a solid and the last element is always a gas
Periods are arranged according to their electronic configuration
As you go across a period (Left to Right), then the atomic radius decreases
Reactivity decreases as you go from left to right across a period
Properties of Metals
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Metals are good conductors of heat and electricity
Metals are shiny
They are ductile and malleable
They are solid at room temperature except mercury (Hg)
They have high densities, and melting and boiling points
They have low ionization energy and low electronegativity
They form metallic bonds
Properties of Non-Metals
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Non-metals are poor conductors of heat and electricity except graphite
Non-metals are not ductile or malleable
Solid non-metals are very weak and brittle which means that they can break easily
They are dull and do not have lustre like metals
Most of the non-metals are gases at room temperature
Non-metals are neither tough nor strong
Non-metals have high ionization energy and high electronegativity
They form covalent bonds
Properties of Metalloids
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Metalloids (metal-like) have properties of both metals and non-metals
Physically they are shiny and brittle solids
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They are semi-conductors of heat and electricity
They usually look like metals but behave largely like non-metals
Metalloids are known to form amphoteric or weakly acidic oxides
They can generally form alloys with metals
They form covalent bonds but sometimes they also form ionic bonds