3-1 Inside Atoms Pages 76-80

nucleus p 76 central core of an atom containing protons and usually neutrons

nucleus

proton p.76 small positively charged particle in the nucleus of an atom

proton

small uncharged (neutral) particle in the nucleus of an atom neutron p 76

neutron

electron p 76 a tiny, negatively charged, high-energy particle that moves in the space outside the nucleus of an atom

electron

Let’s review your answers!

Yes No

Yes No

Yes No Yes

atomic number p 77 the number of protons in the nucleus of an atom

atomic number

mass number p 266 mass number = protons + neutrons also called atomic weight

What is the mass number?

atomic mass unit (amu) p 77 a unit of measurement for the mass of particles in atoms

atomic mass unit (amu) The mass of a proton or a neutron = 1 atomic mass unit 1 neutron = 1 amu 1 proton = 1 amu

atomic mass unit (amu)

How many atomic mass units?

valence electrons p 79 the electrons that are farthest away from the nucleus of an atom and involved in chemical reactions (the # of electrons in the outer-most orbital)

How many valence electrons?

electron dot diagram p. 80 a representation of the number of valence electrons in an atom using dots placed around the symbol of an element

electron dot diagrams

Turn to page 80 Draw the electron dot diagrams for Carbon and Neon in your notes

electron dot diagrams

isotopes p 266 an atom with the same number of protons, but a DIFFERENT number of NEUTRONS from other atoms of the same element

Isotope

isotopes

atomic mass/average atomic massp 82 atomic mass (average atomic mass) is the AVERAGE mass (p + n) of an element’s atoms

atomic mass/average atomic mass atomic mass/ atomic weight

atomic mass/atomic weight vs. mass number atomic mass/atomic weight - average mass for a large group of the same kind of atoms mass number - # of protons + neutrons for 1 specific atom