Question

question 4 of 10
what do all the elements in one row of the periodic table have in common?
a. they all share the same physical properties.
b. they all have the same number of valence electrons.
c. they all have the same number of core electrons
d. they all have similar chemical reactions.

Explanation:

• Option A: Elements in the same row (period) have different physical properties. For example, in period 3, sodium (Na) is a soft metal, while silicon (Si) is a semiconductor.
• Option B: Elements in the same group (column) have the same number of valence electrons, not the same row.
• Option C: In a period (row), as we move from left - to - right, the number of core electrons remains the same. The core electrons are the electrons in the inner shells. For example, in period 2, lithium (Li: \(1s^{2}2s^{1}\)) has \(1s^{2}\) as core electrons, beryllium (\(Be:1s^{2}2s^{2}\)) also has \(1s^{2}\) as core electrons.
• Option D: Elements in the same group (column) have similar chemical reactions because of the same number of valence electrons.

Answer:

C. They all have the same number of core electrons