Correct Answer: Option B

Explanation

The valency of an element is determined by the number of electrons it gains or loses to achieve a stable electron configuration. For an element with the electronic configuration 2, 8, 7, the outermost shell (valence shell) has 7 electrons. To achieve stability, it needs 1 more electron to fill the outermost shell, so its valency is 1.

There is an explanation video available below.

• a truck of mass 20kg moving at a speed of 8m/s, collides with another truck of mass 30kg moving in... Answer this

  0 Answers   ·   2 hours ago
• Passing a thread in and out of a fabric in order to make specific design? Answer this

  1 Answers   ·   14 hours ago
• the leader and the lesson by niyi osun dare is about leadership in Africa.discuss? Answer this

  1 Answers   ·   Literature in English   ·   14 hours ago