Calculating the Number of Electrons in 4.2 Grams of N-

To calculate the number of electrons in 4.2 grams of N-, we need to follow a few steps:

1. Determine the molar mass of N-.
2. Convert the given mass (4.2 grams) to moles.
3. Use Avogadro's number to calculate the number of electrons.

Step 1: Determine the Molar Mass of N-

N- is the negatively charged ion of nitrogen. Its molar mass can be calculated by adding the mass of one nitrogen atom (14.0067 g/mol) to the mass of one extra electron (-0.00054858 g/mol). Therefore, the molar mass of N- is:

Molar mass of N- = 14.0067 g/mol - 0.00054858 g/mol = 14.0062 g/mol

Step 2: Convert the Given Mass to Moles

To convert the given mass of 4.2 grams to moles, we need to divide it by the molar mass of N-.

Number of moles of N- = 4.2 g / 14.0062 g/mol = 0.2998 moles

Step 3: Use Avogadro's Number to Calculate the Number of Electrons

Avogadro's number (NA) is the number of particles (atoms, molecules, ions, etc.) in one mole of a substance. It is equal to 6.022 x 10^23 particles/mol.

To calculate the number of electrons in 0.2998 moles of N-, we can use the following formula:

Number of electrons = NA x number of moles x charge on each ion

N- has a charge of -1, which means it has one extra electron compared to neutral nitrogen. Therefore, the charge on each ion is -1.

Number of electrons = 6.022 x 10^23 particles/mol x 0.2998 moles x (-1) = -1.806 x 10^23 electrons

However, we cannot have a negative number of electrons. This is because electrons are negatively charged particles, so the number of electrons must be expressed as a positive value. Therefore, we need to take the absolute value of the answer.

Number of electrons = 1.806 x 10^23 electrons

Conclusion:

The number of electrons in 4.2 grams of N- with a charge of -1 and 3 will be 1.806 x 10^23 electrons.