Questions: Periods and Groups on the Periodic Table

Question 1

What do elements in the same group of the periodic table have in common?

• A. The same number of protons
• B. The same number of neutrons
• C. Similar chemical properties
• D. The same atomic mass

Answer: (C)

Elements in the same group (vertical column) have similar chemical properties because they have the same number of valence (outer) electrons. This shared electron arrangement causes them to react in similar ways. They do not share the same number of protons, neutrons, or atomic mass.

Question 2

A period on the periodic table is a vertical column.

• T. True
• F. False

Answer: False

A period is a horizontal row, not a vertical column. Vertical columns are called groups (or families). There are 7 periods and 18 groups in the standard periodic table.

Question 3

Name the group of elements found in the far-right column (Group 18) of the periodic table and explain why they are notable.

Model answer: The noble gases (helium, neon, argon, krypton, xenon, radon). They are notable because they are extremely unreactive — they rarely form chemical bonds with other elements.

Noble gases have completely filled outer electron levels, making them exceptionally stable. Because they have no tendency to gain, lose, or share electrons, they almost never participate in chemical reactions. This makes them useful for applications where inertness is desired, such as filling light bulbs (argon) and advertising signs (neon).