Question

Question:
Write the complete symbol for the atom with the given atomic number (Z) and atomic mass (A):

(i) Z = 17, A = 35.

(ii) Z = 92, A = 233.

(iii) Z = 4, A = 9.

Answer 1

Hint:

The complete symbol for an atom is represented as:

$^A_Z \text{X} $

Where:

$ A $ is the atomic mass (number of protons and neutrons combined).

$ Z $ is the atomic number (number of protons, which also determines the element).

$ X $ is the symbol for the element.

Step-by-Step Solution:

1. Identify the element using the atomic number $ Z $ from the periodic table.

2. Write the atomic mass $ A $ as the superscript and atomic number $ Z $ as the subscript, both to the left of the element symbol.

(i) For Z = 17:

The element with atomic number 17 is Chlorine (Cl).

$( ^{35}_{17} \text{Cl} )$

(ii) For Z = 92:

The element with atomic number 92 is Uranium (U).

$( ^{233}_{92} \text{U} )$

(iii) For Z = 4:

The element with atomic number 4 is Beryllium (Be).

$( ^{9}_{4} \text{Be} )$

Answers:

(i)  $^{35}_{17} \text{Cl} $

(ii) $ ^{233}_{92} \text{U} $

(iii) $ ^{9}_{4} \text{Be} $

Note: The atomic number $( Z )$ determines the number of protons in an atom and thus identifies the element. The atomic mass $( A )$, on the other hand, is the sum of the number of protons and neutrons in the atom. Always refer to the periodic table when identifying elements by their atomic number.