Respuesta :

nkirotedoreen46

Answer:

2. X₂O

Explanation:

  • Elements in group 1A are known as alkali metal. Examples include lithium, sodium, and potassium among others.
  • These elements have one valence electron in the outermost energy level and therefore form cations with a charge of +1.
  • They have a valency of 2.
  • Oxygen, on the other hand,has a valency of 2.
  • Therefore, a chemical formula of a compound formed when an element in group 1A say X reacts with oxygen will be X₂O.
  • To write the formula, we identify the symbol of the elements and their valence.
  • Then the atoms of the two elements exchange their valencies which are written as a subscript on each symbol of an element.

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