(a) z = 8, number of neutrons = 9 (b) the isotope of chlorine in which a = 37 (c) z = 27, a = 60 (d) number of protons = 26, number of neutrons = 31 (e) the isotope of i with a mass number of 131 (f) z = 3, number of neutrons = 4 !

Answer;

17/8/O  

37/17/Cl  

57/26/Fe  

131/53/I  

7/3/Li  

-Where the first number listed is A, the second is Z and the element is X

Explanation;

-The number of protons in an atom of an element is its atomic number. The symbol for atomic number is Z.  An atom contains equal numbers of protons and electrons. Since protons and electrons have equal and opposite charges, this means that atoms are have no overall electrical charge.

-The mass number of an atom is its total number of protons and neutrons. The symbol for mass number is A.

-Therefore; number of protons = atomic number

number of electrons = atomic number

number of neutrons = mass number - atomic number