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Atomic Structure Review. atoms. Protons: P + identifies the element Cannot change (atomic number) Neutrons: N o Can change, called isotopes Electrons: E - Can change, called ions Counting Subatomic particles. Atoms can be written 3 different ways Potassium – 39 K – 39 39 K.
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atoms • Protons: P+ identifies the element • Cannot change (atomic number) • Neutrons: No • Can change, called isotopes • Electrons: E- • Can change, called ions Counting Subatomic particles • Atoms can be written 3 different ways • Potassium – 39 • K – 39 • 39K
Electron Configuration Holds 6 electrons Holds 10 electrons (n-1) Holds 2 electrons (n-2) Holds 14 electrons He is actually s because it can only hold 2 electrons
The A group number = the number of valence electrons (except for He) 1A 8A 2A 3A 4A 5A 6A 7A Valence electrons = the # of dots for Lewis Dot Diagrams
The electron structure of an atom determines many of its chemical & physical properties. • (Except for Helium=2) •He•
Examples Ex) 1s2 2s2 2p6 3s2 3p3 = 15 e- = P (count the total electrons to find the atomic number) Ex) [Ar] 4s23d3 = 23 e- = V [ noble gas ] = all of the electrons needed for that noble gas