- #1
Physicslearner500039
- 124
- 6
- Homework Statement
- Excess electrons are placed on a small lead sphere with mass 8.0g so that its net charge is -3.20*10^-9 C. a. Find the number of excess electrons. b. How many excess electrons are there per lead atom? The atomic number of lead is 82, and its atomic mass is 207 g/mol.
- Relevant Equations
- Total Charge q = no of electrons * charge of electron. q = ne
a. This is easy with ## q = n*e ##
## 3.2 * 10^{-9} = n * 1.6*10^{-19} ##
## n = 2*10^{10} ## electrons
b. Total Lead atoms are
## \frac {8 * 6.022*10^{23}} {207} = 2.3 *10^{22} ## I used the Avogadro number.
Total electrons = ## 2.3 * 10^{22} * 82 = 1.88 * 10^{20} ##, here i multiplied with the atomic number of lead.
After that I don't understand how to calculate excess electrons per lead atom. Please advise.
## 3.2 * 10^{-9} = n * 1.6*10^{-19} ##
## n = 2*10^{10} ## electrons
b. Total Lead atoms are
## \frac {8 * 6.022*10^{23}} {207} = 2.3 *10^{22} ## I used the Avogadro number.
Total electrons = ## 2.3 * 10^{22} * 82 = 1.88 * 10^{20} ##, here i multiplied with the atomic number of lead.
After that I don't understand how to calculate excess electrons per lead atom. Please advise.