Question

select the correct answer. which of these pairs of elements have the same number of valence electrons? a. oxygen (o) and bromine (br) b. selenium (se) and bromine (br) c. carbon (c) and lead (pb) d. oxygen (o) and carbon (c) e. sodium (na) and magnesium (mg)

Explanation:

Elements in the same group of the periodic table have the same number of valence electrons:

• A. Oxygen (Group 16) has 6 valence electrons; Bromine (Group 17) has 7 valence electrons.
• B. Selenium (Group 16) has 6 valence electrons; Bromine (Group 17) has 7 valence electrons.
• C. Carbon (Group 14) and Lead (Group 14) both have 4 valence electrons.
• D. Oxygen (Group 16) has 6 valence electrons; Carbon (Group 14) has 4 valence electrons.
• E. Sodium (Group 1) has 1 valence electron; Magnesium (Group 2) has 2 valence electrons.

Answer:

C. carbon (C) and lead (Pb)