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Chapter 4. What are subatomic particles?. Are parts of matter that make up atoms. protons, electrons, and neutrons. subatomic particles. Particle. Symbol. Charge. Mass. Proton. p +. 1+. 1. Neutron. n. 0. 1. Electron. e -. 1-. Atomic Number. Is the number of protons in an atom.
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What are subatomic particles? • Are parts of matter that make up atoms. • protons, electrons, and neutrons
subatomic particles Particle Symbol Charge Mass Proton p+ 1+ 1 Neutron n 0 1 Electron e- 1-
Atomic Number • Is the number of protons in an atom. • all atoms of an element have the same number of protons • Each element has a unique atomic number
atoms are neutral • the number of protons is equal to the number of electrons • the charges balance
Mass Number • is the total number of protons plus neutrons. • For example Oxygen contains 8 protons and 8 neutrons so its mass number is 16 • to find the number of neutrons subtract the number atomic number from the mass number. • number of neutrons = mass number - atomic number.
How many neutrons does Gold-197 have? • gold has a atomic number of 79 and a mass number of 197. • number of neutrons = mass number - atomic number • number of neutrons = 197 – 79 • number of neutrons = 118
Isotopes • are atoms of the same element with different numbers of neutrons. • isotopes have different mass numbers • to distinguish isotopes, isotopes are referred to by there mass numbers • Example Oxygen-16 and Oxygen-17 • Oxygen-16 has 8 p+ and 8 n • Oxygen-17 has 8 p+ and 9 n
Home work • Section 4.2 work sheet • Read section 4.3 page 113 - 118