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:

${}_Z^A\text{X}$

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).

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

(ii) For Z = 92:

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

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

(iii) For Z = 4:

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

${(}_4^9\text{Be})$

Answers:

(i)  ${}_{17}^{35}\text{Cl}$

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

(iii) ${}_4^9\text{Be}$

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.