Which of the following elements is not in Group 1 of the periodic table?Group of answer choicesLithiumpotassiumHeliumHydrogen

Step 1: Break Down the Problem

To find which element is not in Group 1 of the periodic table, let's examine the provided elements: Lithium, Potassium, Helium, and Hydrogen.

Step 2: Relevant Concepts

• Group 1 elements, also known as alkali metals, include Lithium (Li), Sodium (Na), Potassium (K), Rubidium (Rb), Cesium (Cs), and Francium (Fr).
• Helium (He) is a noble gas located in Group 18 of the periodic table.

Step 3: Analysis and Detail

1. Lithium (Li): This is an alkali metal and belongs to Group 1.
2. Potassium (K): Also an alkali metal located in Group 1.
3. Helium (He): A noble gas which is not in Group 1, it is located in Group 18.
4. Hydrogen (H): Although it is located at the top of Group 1, it does not share the same properties as alkali metals.

Step 4: Verify and Summarize

Based on the analysis, Helium (He) is confirmed to be the element that is not in Group 1 of the periodic table.

Final Answer

Helium is the element that is not in Group 1 of the periodic table.