Question

The number of electrons in an element X is 6 and the number of neutron is 8. Which of the following is the correct representation of the element ?

• A. \({}^{8}_{6}\text{X}\)
• B. \({}^{14}_{6}\text{X}\)
• C. \({}^{6}_{8}\text{X}\)
• D. \({}^{14}_{8}\text{X}\)

Hint:

Remember the notation \({}^{A}_{Z}\text{X}\):
\(Z\) (bottom number) = Atomic Number = Number of Protons. (For neutral atom, also = Number of Electrons).
\(A\) (top number) = Mass Number = Number of Protons + Number of Neutrons. Given electrons = 6 \(\rightarrow\) protons (\(Z\)) = 6. Given neutrons = 8. Mass number (\(A\)) = protons + neutrons = \(6 + 8 = 14\). So, \({}^{14}_{6}\text{X}\).

Answer 1

The Correct Option is B

Concept: The standard notation for representing an element (or isotope) is \({}^{A}_{Z}\text{X}\), where:
\(\text{X}\) is the chemical symbol of the element.
\(Z\) is the Atomic Number (number of protons).
\(A\) is the Mass Number (number of protons + number of neutrons). Step 1: Given information
Number of electrons in element X = 6.
Number of neutrons in element X = 8. Step 2: Determine the Atomic Number (\(Z\)) For a neutral atom (which an "element" generally implies unless specified as an ion), the number of electrons is equal to the number of protons. Number of protons = Number of electrons = 6. The Atomic Number (\(Z\)) is defined as the number of protons. So, \(Z = 6\). (An element with atomic number 6 is Carbon, C, but the symbol X is used here). Step 3: Determine the Mass Number (\(A\)) The Mass Number (\(A\)) is the sum of the number of protons and the number of neutrons. Number of protons = 6 Number of neutrons = 8 So, \(A = \text{Number of protons} + \text{Number of neutrons} = 6 + 8 = 14\). Step 4: Write the correct representation Using the notation \({}^{A}_{Z}\text{X}\): Substitute \(A=14\) and \(Z=6\). The representation is \({}^{14}_{6}\text{X}\). Step 5: Compare with the options
(1) \({}^{8}_{6}\text{X}\): Mass number is incorrect.
(2) \({}^{14}_{6}\text{X}\): This matches our derived representation.
(3) \({}^{6}_{8}\text{X}\): Atomic number and mass number positions/values are incorrect.
(4) \({}^{14}_{8}\text{X}\): Atomic number is incorrect. Therefore, the correct representation is \({}^{14}_{6}\text{X}\).