What does below chemistry rebus means?

What word is represented by this rebus?

What is the fewest number of coins that would be required in order to make sure each and every coin touches exactly three other coins?

John is a strange liar.

He lies on six days of the week, but on the seventh day, he always tells the truth.

He made the following statements on three successive days:

Day 1: "I lie on Monday and Tuesday."
Day 2: "Today, it"s Thursday, Saturday, or Sunday."
Day 3: "I lie on Wednesday and Friday."

On which day does John tell the truth?

What is the last thing you take off before bed?

Can you solve this amazing hard number series problem?
7, 8, 10, 12, 16, 18 ?

Can you count the number of matches in the picture below ?

John and Jenni are a married couple. They have two kids, one of them is a girl. Assume safely that the probability of each gender is 1/2.
What is the probability that the other kid is also a girl?

Hint: It is not 1/2 as you would first think.

My location can be determined by the below rebus.
So where am i ?

A king sentenced a man to the death sentence for some crime he had committed. Known for his kindness, the king told the culprit that he had a choice to die in a way he decides.

The culprit was clever and said something that saved him from death. What method do you think he must have chosen for his death?