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10 Cards in this Set
- Front
- Back
- 3rd side (hint)
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The most stable, unreactive atoms in the Periodic Table are the _____ _____.
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Noble gases.
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Why do atoms combine and how?
Name this bond. |
By sharing electrons so that all their outer energy levels are full.
This is called a covalent bond. |
xx
| xx -- F -- x | xx ^ ^ ^ Fluorine 9e (2,7) xx | x -- Cl -- xx | xx ^ ^ ^ Chlorine 17e (2,8,7) xx xx | | xx -- F -- xx -- Cl -- xx | | xx xx = ClF |
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Define:
Diotomic molecule |
A molecule with two atoms.
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A number of elements in the Periodic Table go around in pairs, eg;
xx xx | | xx -- F -- xx -- F-- xx | | xx xx Fluorine 9e (2,7) + Fluorine 9e (2,7) Chemical formula = F2 |
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Name the diotomic elements.
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Bromine, Oxygen, Nitrogen, Chlorine, Hydrogen, Iodine, Fluorine.
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(p.1 of data booklet)
Remeber BONCHIF! B - Bromine O - Oxygen N - Nitrogen C - Chlorine H - Hydrogen I - Iodine F - Fluorine |
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What is a covalent bond?
(General Level) |
General Level
Atoms joined by sharing electrons so that each atom has a full outer energy level. |
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What is a covalent bond?
(Credit Level) |
Credit Level
The overlapping energy levels are held together because each one is attracted to the nucleus of the other atom. |
NOTE: For Credit level, more detail is needed in answering.
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Define:
Covalent Bond |
Two positive nuclei are held together by their common attraction for the shared electrons in the bond.
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Give the valency of each group of the periodic table.
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1 = 1
2 = 2 3 = 3 4 = 4 5 = 3 6 = 2 7 = 1 0(8) = 0 |
(see p.1 of data booklet)
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Explain how valency can be worked out and remembered.
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The valency is the same as the number of half-filled electron clouds.
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Group no. in Periodic Table
1 2 3 4 5 6 7 0(8) Number of electrons in outer level 1 2 3 4 5 6 7 8 Number or half-filled electron clouds* 1 2 3 4 3 2 1 0 Valency or Combining Power 1 2 3 4 3 2 1 0 Clearly the valency is the SAME as the no. of half-filled electron clouds. *If unsure of 'electron cloud' meaning, see bonding diagram... the 'petals' or 'bits sticking out' are the clouds!* |
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Balance the equation:
C2H4 + O2 --> CO2 + H2O |
2C2H4 + 6O2 --> 4CO2 + 4H2O
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Imagine chemical equations are like a see-saw... there has to be the SAME on both sides so that it can balance.
Example: Na + S --> Na2S Na = 1 Na = 2 S = 1 S = 1 2Na + S --> Na2S Na = 2 Na = 2 S = 1 S = 1 Now it is balanced on both sides. NOTE: Balancing numbers ALWAYS go in FRONT of the formulas to be balanced. |
