Which of the following elements are included in the same group in the periodic table?

H, Li, Na, K

The correct answer is 4. H, Li, Na, K.

Let us break down the elements in the selected option:

Option 4 includes the elements:
Hydrogen (H)
Lithium (Li)
Sodium (Na)
Potassium (K)

All these elements are in the same column or group in the periodic table, specifically in Group 1 (alkali metals). In Group 1, elements have similar chemical properties, and they share common characteristics such as having one valence electron. Here's a brief overview of each element:

1. Hydrogen (H):

While hydrogen is not an alkali metal, it is often included in discussions about Group 1 due to its properties. It has one electron in its outer shell.

2. Lithium (Li):

Lithium is the first alkali metal in Group 1. It has one valence electron and is known for its reactivity.

3. Sodium (Na):

Sodium is the second alkali metal in Group 1. Like lithium, it is highly reactive and has one valence electron.

4. Potassium (K):

Potassium is the third alkali metal in Group 1. It shares similar properties with lithium and sodium, exhibiting high reactivity due to the presence of one valence electron.

In summary, the elements hydrogen, lithium, sodium, and potassium are indeed included in the same group (Group 1) of the periodic table, making option 4 the correct choice.