How many atoms are present in 8.00g of He?

1.20 × 10²⁴ atoms He

General Formulas and Concepts:

Chemistry - Atomic Structure

Explanation:

Step 1: Define

8.00 g He

Step 2: Identify Conversions

Avogadro's Number

Molar Mass of He - 4.00 g/mol

Step 3: Convert

= 1.2044 × 10²⁴ atoms He

Step 4: Check

We are given 3 sig figs. Follow sig fig rules and round.

1.2044 × 10²⁴ atoms He ≈ 1.20 × 10²⁴ atoms He

explanation:

let the different atoms be x and y. each with four protons and same mass will be represented as follows.

mass number is number of protons + number of neutrons.

            and  

since, it is given that one has a negative charge while the other is neutral. therefore, there will be increase in number of protons and the atom will be represented as follows.

according to periodic table, mass number of beryllium is 9 and it has atomic number 4 so, the atoms will be and .  

the protons and neutrons will be located inside the nucleus whereas the electrons will be revolving around the nucleus.