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Electron Configuration. How Many Electrons are In an Atom?. In an ATOM, . 3. Li. # Electrons = # Protons = Atomic Number. 6,7. 6.94. lithium. 3 Ways to Tell How Many Electrons. 3 Ways to Tell How Many Electrons. 3 Ways to Tell How Many Electrons. 3 Ways to Tell How Many Electrons.
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How Many Electrons are In an Atom? • In an ATOM, 3 Li # Electrons = # Protons = Atomic Number 6,7 6.94 lithium
3 Ways to Tell How Many Electrons Yesterday Today Tomorrow
Background Information Energy Level – distance away from the nucleus in which electron “resides” -Think Bohr model- Represented by 1, 2, 3, 4…
Background Information Orbital – regions in energy levels that have similar shapes Represented by s, p, d, f
Background Information s = Sphere
Background Information p = dumbbell
Background Information d = clover
Background Information f= complicated Care to try??
Steps for determining Electron Configuration Step Example - Li • Find the atomic number of the element – this is # electrons Atomic # = 3 Li has 3 electrons
Steps for determining Electron Configuration Step Example - Li • Put the electrons in their orbitals 3 electrons
Step 2 Pauli Exclusion Principle – no more than two electrons per orbital
Step 2 Aufbau Principle – electrons fill lowest energies first
Step 2 Hund’s Rule - Electrons will stay unpaired in each energy level for as long as possible
Steps for determining Electron Configuration Step Example - Li • Write electron configuration 3 electrons
Steps for determining Electron Configuration Report: Energy Level # electrons Orbital
Steps for determining Electron Configuration Step Example - Li • Write electron configuration. 3 electrons 1s22s1
Example 2 - Sulfur • Atomic # = 16 • Electron Configuration: 1s22s22p63s23p4
Example 3 - Arsenic • Atomic # = 33 • Electron Configuration: 1s22s22p63s23p64s23d104p3
Example 4 - Carbon • Atomic # = 6 • Electron Configuration: 1s22s22p2
Getting into an Excited State • An electron in an excited state is in a higher state (orbital and/or energy level) than it usually is • Ground state – normal level for an electron
Excited State • When the electron receives energy it jumps from the ground state to a higher level • This electron will then fall back down to the ground state
Excited State- What’s it look like? • Remember the Lithium ground state? 1s22s1 • What if we make an electron excited? • It’ll jump up in energy! s p Excited State Lithium-1s22p1
On Your Own • Try Helium, Oxygen, Calcium, and Bromine with a Partner • Then do the rest BY YOURSELF!! • (Ask QUESTIONS when you need!!)