How many different atoms does it take to make up the most essential molecules of life?

Elemental composition of average human is mostly the first 6 on the list CHNOPS- carbon, hydrogen, nitrogen, oxygen, phosphorus, sulfur

1. Oxygen (65%)

2. Carbon (18%)

3. Hydrogen (10%)

4. Nitrogen (3%)

5. Calcium (1.5%)

6. Phosphorus (1.0%)

7. Potassium (0.35%)

8. Sulfur (0.25%)

9. Sodium (0.15%)

10. Magnesium (0.05%)

11. Copper, Zinc, Selenium, Molybdenum, Fluorine, Chlorine, Iodine, Manganese, Cobalt, Iron (0.70%)

12. Lithium, Strontium, Aluminum, Silicon, Lead, Vanadium, Arsenic, Bromine (trace amounts)

Firstly, do you mean elements, not atoms? You need millions of atoms to make up the tiniest virus.

Also, it depends on what you mean by essential. In order of importance, I think I'd have to go:

Hydrogen, Oxygen (predominantly water, whose properties are vital for life), Carbon (there's really no way you could have life without carbon), and then probably nitrogen. Things like sulphur and phosphorus start to come in some time after that; but one thing everyone seems to have missed is electrolytes. It's not immediately clear to me whether they're absolutely essential for life (they're certainly completely vital for life as we know it), or are just the background that we've made extensive use of - but you really wouldn't have life at all without sodium, potassium and probably calcium. I'd be inclined to put them about sulphur and phosphorous, myself. Chlorine (as chloride ions) is a lot less important than the cations, I think. Then you have trace metals further down.

The essential molecules of life are proteins, carbohydrates, lipids, and nucleic acids.

Those molecules are made up of only 6 DIFFERENT atoms: C, H, O, N, S, and P.

There are lots of other atoms involved in the metabolism of living cells, but these 6 are the only ones that are actually covalently bonded to each other to make proteins, carbohydrates, lipids, and nucleic acids.

DNA,

Carbon, Hydrogen, Oxygen, Phosphorus, Nitrogen {I think that's it, but double check}

Protien

Carbon, Hydrogen, Oxygen, Nitrogen, Sulfer {maybe others in R groups}

Lipids

Carbon, Hydrogen, Oxygen, Phosphorus

water, hydrogen, oxygen.

Any others you need?

1for basic life

For humans it requiers 18 different types (as far as we know )and billions of them