Study Guides/Chemistry/Atomic Number of Na (Sodium)
Study Guide · Chemistry

What is the Atomic Number of Na (Sodium)?

In chemistry, 'Na' is the chemical symbol for Sodium. The symbol comes from its Latin name, 'Natrium'. Sodium is an essential element, famous for being highly reactive and a primary component of table salt.

Question (Click to Flip)

What happens when Sodium reacts with Chlorine?

Answer

Sodium (Na) gives its 1 outer electron to Chlorine (Cl), forming an ionic bond. This creates Sodium Chloride (NaCl), which is common table salt.

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Key Facts

Sodium is a very soft metal; it can easily be cut with a standard butter knife.

Because of its high reactivity with oxygen and moisture in the air, sodium must be stored completely submerged in kerosene oil.

The atomic mass of Sodium is approximately 23 amu.

1. The Atomic Number

The atomic number of Na (Sodium) is 11.

This means that a neutral sodium atom contains exactly 11 protons in its nucleus and 11 electrons orbiting around it.

2. Electronic Configuration

Because it has 11 electrons, they are distributed in the shells as follows:

  • K shell: 2 electrons
  • L shell: 8 electrons
  • M shell: 1 electron Configuration: 2, 8, 1.

3. Why is Sodium so Reactive?

Sodium belongs to Group 1 of the periodic table (Alkali Metals). Because it has exactly 1 valence electron in its outermost shell, it is desperately trying to give that electron away to achieve a stable, full outer shell (octet). This makes sodium extremely reactive. It reacts violently with water to form sodium hydroxide and highly flammable hydrogen gas.

Questions and Answers

What happens when Sodium reacts with Chlorine?+

Sodium (Na) gives its 1 outer electron to Chlorine (Cl), forming an ionic bond. This creates Sodium Chloride (NaCl), which is common table salt.

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