Three different atoms of oxygen are represented as:
(i) What do the subscripts (lower figures) and superscripts (upper figures) represent?
(ii) What factor is responsible for the change in the superscripts 16, 17 and 18, though the element is the same?
(iii) What is the usual name for such atoms of an element?
(iv) Give the nuclear composition of 
(i) The subscripts (lower figures) represents the atomic number and the superscripts (upper figures) represents the mass number.
(ii) The factor is responsible for the change in the superscripts 16, 17 and 18, though the element is the same number of neutrons.
(iii) The usual name for such atoms of an element is isotopes.
(iv) The nuclear composition of 
is that it have 8 protons and 10 neutrons
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