Which of the following element does not contain 'one' electron in its valance shell?

Question

Question

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NPCIL Stipendiary Trainee 2021 Official Paper-I

Answer 1

The correct answer is Ca.

Key Points

Calcium (Ca) has two electrons in its valence shell (4th shell).
The electronic configuration of Calcium (Ca) is 2, 8, 8, 2.
Calcium belongs to Group 2 (alkaline earth metals) in the periodic table, where elements typically have two valence electrons.
Unlike Na (Sodium), Li (Lithium), and H (Hydrogen), which have one electron in their valence shell, Ca has two.

Additional Information

Valence Electrons:
- Valence electrons are the electrons in the outermost shell of an atom.
- These electrons are important for chemical bonding and reactions.
Periodic Table Groups:
- Elements in the same group have similar properties and the same number of valence electrons.
- Group 1 elements (alkali metals) have one valence electron.
- Group 2 elements (alkaline earth metals) have two valence electrons.
Electron Configuration:
- Electron configuration describes the distribution of electrons in an atom's orbitals.
- It follows the Pauli exclusion principle, Hund's rule, and the Aufbau principle.
Reactivity of Elements:
- Elements with one valence electron (e.g., Na, Li, H) are highly reactive.
- Elements with two valence electrons (e.g., Ca) are less reactive but still more reactive than those with a full valence shell.

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