The elements in a periodic table is placed in order of increasing atomic number (Z), which we know is a fundamental property of the element - number of protons in the nucleus of its atom. To read the periodic table, simply start from the top left and read across. You will find that the atomic number increases.
3.1.2 Distinguish between the terms group and period
Group is the columns or the vertical elements. Period is the row or the horizontal elements.
3.1.3 Apply the relationship between the electron arrangement of elements and their position in the periodic table up to Z=20.
Groups state how many valence electrons there are
Periods state how many electron shells there are.
Valence electron is an electron in the outer shell of an atom
Example,
Carbon has an electron arrangement of 2, 6
It is in the 2nd period and 6th group, hence its position on the periodic table
Calcium has an electron arrangement of 2, 8, 8, 2
It is in the 4th period and 2nd group, hence its position as an alkali earth metal.
3.1.4 Apply the relationship between the number of electrons in the highest occupied energy level for an element and its position in the periodic table
An atom with one valence electron will be in group 1
2, 1 would be in group 1
An atom with two valence electron will be in group 2
2, 2 would be in group 2
...etc
An atom with a full outer shell will be in group 0
2, 0 would be in group 0
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