# Atoms & Elements

1. How many protons, neutrons and electrons are present in one atom of the following:
1. 1H
2. 2H
3. 3H
4. 13N
5. 14N
6. 15N
7. 79Br
8. 81Br1-
9. 262Bh
2. What is the Atomic Weight of chlorine given that:
• The exact mass of 35Cl is 34.9689 and the relative abundance is 75.53%
• The exact mass of 37Cl is 36.9659 and the relative abundance is 24.47%

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3. What is the Atomic Weight of ruthenium given the following information from WebElements:
Isotope Abundance Exact Mass
96Ru 5.54% 95.907599
98Ru 1.87% 97.905287
99Ru 12.76% 98.9059389
100Ru 12.60% 99.9042192
101Ru 17.06% 100.9055819
102Ru 31.55% 101.9043485
104Ru 18.62% 103.905424

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4. Calculate the number of moles in:
1. 20.1797 g of Ne
2. 45.3594 g of Ne
3. 0.198669 g of Ne
4. 0.198669 g of Ta
5. Calculate the mass of:
1. 1.00 mol of Fe
2. 2.00 mol of Fe
3. 4.362 x 10-5 mol of Fe
4. 4.362 x 10-5 mol of Li
6. Using a blank periodic table, fill in the atomic number, name, atomic symbol, and atomic weight of the first 36 elements. Also label the noble gases, the halogens, the alkali metals, the metals, and the non-metals.
7. Use the mass spectrum for chromium given below to determine the atomic weight.