Question

An element X has $7$ electrons in its L shell. What is true about the element?
I. It belongs to period $9$ of a modern periodic table.
II. Its atom contains $9$ protons.
III. It has a valency of $7$.
IV. Its atoms can accept one electron to acquire noble gas configuration.

• A. (I) and (II)
• B. (II) and (III)
• C. (III) and (IV)
• D. (II) and (IV)

Answer 1

Answer: (D)

(II) and (IV)

An element $X$ has 7 electrons in its $L$ shell. The statements (II) and (IV) are true about the element.
I. It belongs to period 2 of modern periodic table.
II. Its atom contains 9 protons. Its atomic number is 2. It has 2 electrons in $K$ shell and 7 electrons in $L$ shell.
III. It has a valency of 1.
IV. Its atoms can accept an electron to acquire noble gas configuration.
Hence, the option (D) is correct answer.
Note: Element $X$ is halogen. It is fluorine.