Atomic Structure Worksheet Answers

Basic Atomic Structure Worksheet **Key** 1. The 3 particles of the atom are: a. protons (+) b. electrons (-) c. neutrons (0) Their respective charges are: a. positive b. negative c. no charge 2. The number of **protons** in one atom of an element determines the atom's **symbol** and the number of **electrons** determines the **charge** of the element. 3. The atomic number tells you the number of **protons** in one atom of an element. It also tells you   the "identity" of an element as well as its location on the periodic table. No two different elements will have the **same** atomic number. 4. The **mass** of an element is the average mass of an element's naturally occurring   atoms, or isotopes, taking into account the number of **neutrons** of each isotope. 5. The **mass number** of an atom of an element is the total number of protons and neutrons in the **nucleus** of the atom. 6. The mass number is used to calculate the number of **neutrons** in one atom of an element. In order to calculate the number   of neutrons you must **subtract** the **number** of **protons** from the **mass number**.   7. Give the symbol of and the number of protons in one atom of: Lithium Li, 3p⁺ Bromine Br, 35p⁺ Iron Fe, 26p⁺ Mercury Hg, 80p⁺ Oxygen O, 8p⁺ Copper Cu, 29p⁺ Helium He, 2p⁺ Krypton Kr, 36p⁺ 8. Give the symbol of and the number of electrons in a neutral atom of: Uranium U, 92e⁻ Boron B, 5e⁻ Chlorine Cl, 17e⁻ Iodine I, 53e⁻ Xenon Xe, 54e⁻ 9. Give the symbol of and the number of neutrons in one atom of: (Mass numbers are ALWAYS whole numbers - show your calculations)   Bismuth Bi, 209 - 83 = 126n⁰ Fluorine F, 19 - 9 = 10n⁰ Carbon C, 12 - 6 = 6n⁰ Hydrogen H, 1 - 1 = 0n⁰ Europium Eu, 152 - 63 = 89n⁰ Mercury Hg, 201 - 80 = 121n⁰ 10. Name the element which has the following numbers of particles: a. 26 electrons, 29 neutrons, 26 protons: Iron b. 53 protons, 74 neutrons: Iodine c. 2 electrons (neutral atoms):   Helium d. 20 protons: Calcium e. 86 electrons, 125 neutrons, 82 protons:   Lead f. 0 neutrons: Hydrogen 11. If you know ONLY the following information can you ALWAYS determine what the element is? (Yes/No) a. Number of protons: Yes b. Number of neutrons: No c. Number of electrons in a neutral   atom: Yes d. Number of electrons: No 12. Fill in the missing items in the table below.   | NAME | SYMBOL | # PROTONS | ELECTRONS | NEUTRONS | ISOTOPIC SYMBOL | |--------------|---------|------------|------------|------------|-----------------| | Sodium | Na | 11 | 11 | 12 | ²³Na | | Chlorine | Cl | 17 | 17 | 18 | ³⁵Cl | | Potassium | K | 19 | 19 | 20 | ³⁹K | | Phosphorus | P | 15 | 15 | 16 | ³¹P | | Iodine | I | 53 | 53 | 74 | ¹²⁷I | | Silver | Ag | 47 | 47 | 61 | ¹⁰⁸Ag | | Krypton | Kr | 36 | 36 | 48 | ⁸⁴Kr | | Tungsten | W | 74 | 74 | 110 | ¹⁸⁴W | | Copper | Cu | 29 | 29 | 35 | ⁶³Cu | | Gold | Au | 79 | 79 | 118 | ¹⁹⁷Au | | Sulfur | S | 16 | 16 | 16 | ³²S |