Question

carbon (c) and oxygen (o) are in the same period on the periodic table and have the same number of electron shells or energy levels. carbon (c) and oxygen (o) are in different periods on the periodic table and have different numbers of electron shells or energy levels. carbon (c) and oxygen (o) are in the same group on the periodic table and have the same number of valence electrons. carbon (c) and oxygen (o) are in the same period on the periodic table and have the same number of valence electrons. carbon (c) and oxygen (o) are in different groups on the periodic table and have different numbers of total electrons. carbon (c) and oxygen (o) are in the same period on the periodic table and have different atomic numbers

Explanation:

• In the periodic table, elements in the same period have the same number of electron shells. Carbon and oxygen are both in period 2, so they have 2 electron shells.
• Atomic number is unique for each element. Carbon has an atomic number of 6, and oxygen has an atomic number of 8.

Answer:

Carbon (C) and oxygen (O) are in the same period on the periodic table and have different atomic numbers.