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Atoms. Atom. Smallest part of an element with all the properties of that element. 2 parts. 1. Nucleus. Center of atom most of atomic mass contains protons & neutrons. Nucleus. Mass Number. Mass # = Mass of the nucleus 1 proton = 1amu (atomic mass unit) 1 neutron = 1 amu
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Atom • Smallest part of an element with all the properties of that element. • 2 parts
1. Nucleus • Center of atom • most of atomic mass • contains protons & neutrons Nucleus
Mass Number • Mass # = Mass of the nucleus • 1 proton = 1amu (atomic mass unit) • 1 neutron = 1 amu • The average # protons + # neutrons • Electrons too small to contribute to mass 5 B Boron 10.81 Mass
What is the mass (rounded to the nearest whole number) of an atom of each of these elements? • 11 • 23 • 22.99 • 22 • 24 • 51 • 51.99 • 52 • 36 • 83 • 83.80 • 84 Na = 23 Cr = 52 Kr = 84
- - 2. Electron Cloud • Cloud of electrons that surrounds the nucleus • Individual electrons move so fast, they appear as a cloud • Most of the volume of the atom. • Mostly empty space. Electron Cloud
3 subatomic particles • Protons: positive charge (+) located in nucleus • Neutrons: neutral charge (=) located in nucleus • Electrons: negative charge (-) located in the electron cloud
5 B Boron 10.81 - - - - - = + + = = Atomic Number + = = = + + Protons • # protons (positive charges) = atomic # • Atoms of different elements have different numbers of protons.
How many protons (+) are in the nucleus of an atom of each of these elements? • 11 • 23 • 22.99 • 22 • 24 • 51 • 51.99 • 52 • 36 • 83 • 83.80 • 84 Kr = 36+ Na = 11+ Cr = 24+
Different elements have different numbers of protons (+). • Which atom has 8 protons? • Which atom has 6 protons? • Which atom has 7 protons? A. Carbon B. Nitrogen C. Oxygen D. Moccium Oxygen Carbon Nitrogen
5 B Boron 10.81 - - - - - = + + = = + = = = + + Neutrons • # neutrons (neutral, no charge) = mass – protons (atomic #) Atomic Number (# protons) 11 (rounded) -5 6 neutrons Mass (# protons + # neutrons
How many neutrons (=) are in the nucleus of an atom of each of these elements? • 11 • 12 • 22.99 • 22 • 24 • 26 • 28 • 52 • 36 • 48 • 83.80 • 84 Na 23 -11 12 = Cr 52 -24 28 = Kr 84 -36 48 =
5 B Boron 10.81 - - - - - = + + = = Atomic Number + = = = + + Electrons • # electrons (negative) = # protons (atomic #) • # negative charges = # positive charges, the atom is neutrally charged (has no charge)
How many electrons (-) are in the electron cloud of an atom of each of these elements? • 11 • 23 • 22.99 • 22 • 24 • 51 • 51.99 • 52 • 36 • 83 • 83.80 • 84 Na = 11- Cr = 24- Kr = 36-
13 B. 14 • C. 26 D. 27 13 + 13 Al Aluminum 26.98 • How many protons (+) does an atom of Aluminum have? • How many electrons (-) does an atom of Aluminum have? • How many neutrons (=) does an atom of Aluminum have? • 13 B. 14 • C. 26 D. 27 13 - 27 (mass #) -13 (atomic #) 14 = • 13 B. 14 • C. 26 D. 27
12 B. 13 • C. 24 D. 25 12 + 12 Mg Magnesium 24.31 • How many protons (+) does an atom of Magnesium have? • How many electrons (-) does an atom of Magnesium have? • How many neutrons (=) does an atom of Magnesium have? • 12 B. 13 • C. 24 D. 25 12 - 24 (mass #) -12 (atomic #) 12 = • 12 B. 13 • C. 24 D. 25
15 B. 16 • C. 30 D. 31 15 + 15 P Phosphorus 30.97 • How many protons (+) does an atom of Phosphorus have? • How many electrons (-) does an atom of Phosphorus have? • How many neutrons (=) does an atom of Phosphorus have? • 15 B. 16 • C. 30 D. 31 15 - 31 (mass #) -15 (atomic #) 16 = • 15 B. 16 • C. 30 D. 31
How many protons (+), neutrons (=), and electrons (-) does an atom of Boron have? • 5 (+), 5(=), 5(-) B. 11(+), 11(=), 11(-) • C. 5 (+), 6(=), 5(-) D. 5(+), 11(=), 5(-) • What is the atomic # of Neon, and how many protons (+) and neutrons (=) does an atom of it have? • At#10, 20(+), 10(=) B. At#10, 10(+), 10(=) • C. At#20, 10(+), 10(=) D. At#10, 10(+), 20(=) • What is the atomic # and mass of Fluorine, and how many electrons (-) does an atom of it have? • At#10, mass 19, 10(-) B. At#19, mass 9, 9(-) • C. At#9, mass 10, 9(-) D. At#9, mass 19, 9(-) Fill in the table below. 6 5 5 10 10 10 19 9 9
5 B Boron 10.81 - - - - - = + + = = 2nd Row + = = = + + Energy Levels • # shells = # of ROW on Periodic Table 2 Energy Levels
5 B Boron 10.81 - - - - - = + + = = 5 Electrons + = = = + + Where do the Electrons go? • 1st Shell = No more than 2 • 2nd Shell = No more than 8 • 3rd Shell = No more than 8 • Last Shell = # of COLUMN on Periodic Table 2 Electrons in 1st shell B is in 3rd Column 3 electrons in last shell
Diagram Atoms 1 -18 • Teacher demonstrates diagramming atoms with atomic #1, #2, #3, #10, #18 • Students work with partners – one sheet of paper per team. • Take turns diagramming the atoms. While one draws, the other checks work. • One person diagrams the odd numbered elements, partner checks work. • The other person diagrams the even numbered elements, partner checks work.