3. Subatomic particles Electron Proton Neutron NameSymbolCharge Relative mass Actual mass (g) e-e- p+p+ n0n0 +1 0 1/1840 1 1 9.11 x 10 -28 1.67 x 10 -24 Q. Which particles are responsible for the mass of the atom?

4. 1. Atomic mass is also called mass number. Mass Number = the number of protons + neutrons (All the things with mass) 1. Atomic mass is also called mass number. Mass Number = the number of protons + neutrons (All the things with mass) Q. Which particles are used to identify an atom?

5. 2. Atomic Number (proton number) = number of protons n # of protons determines kind of atom n the same as the number of electrons in the neutral atom X Use your periodic tables to identify the atomic number and atomic mass of element X. a b

6. Symbols n Contain the symbol of the element, the mass number and the atomic number X Mass number Atomic number

7. Nucleons: This is all the particles that make up the nucleus. This is equal to the protons + neutrons. Nucleons: This is all the particles that make up the nucleus. This is equal to the protons + neutrons. Q. How can you find the number of neutrons in an atom?

8. Symbols n Find the –number of protons –number of neutrons –number of electrons –Atomic number –Mass Number F 19 9

9. Symbols n Find n Find the –number –number of protons of neutrons of electrons –Atomic –Atomic number –Mass –Mass Number Br 80 35

10. Symbols n if an element has an atomic number of 34 and a mass number of 78 what is the –number of protons –number of neutrons –number of electrons –Complete symbol

11. Symbols n if an element has 91 protons and 140 neutrons what is the –Atomic number –Mass number –number of electrons –Complete symbol

12. Symbols n if an element has 78 electrons and 117 neutrons what is the –Atomic number –Mass number –number of protons –Complete symbol