Periodic Trends
What are periodic trends?
Trends in the pattern of properties in the elements on the periodic table.
Balance the equation.
PCl3 ➡ P4 + Cl2
4PCl3 ➡ 1P4 + 6Cl2
A + B ➡ AB
Combination / Synthesis
Assign each element an oxidation number.
CO2
C= +4
O= -2
O2= -4
What does the pH scale measure?
The pH scale measures acidity or basicity of a substance.
Does atomic radius increase or decrease as you move across a period?
Decreases
Balance the equation.
SO3 ➡ SO2 + O2
2SO3 ➡ 2SO2 + 1O2
AB ➡ A + B
Decomposition
Assign each element an oxidation number.
OF2
O= +2
F= -1
F2= -2
What does a pH of 4.5 make a substance? Acidic or basic?
Acidic
What is electronegativity?
It is a measure of how strongly an atom attracts electrons when it forms a chemical bond.
Balance the equation.
F2 + H2O ➡ OF2 + HF
2F2 + 1H2O ➡ 1OF2 + 2HF
AB + O2 ➡ CO2 + H2O + 💥
Combustion
Assign each element an oxidation number.
CuNO3
Cu= +1
N= +5
O= -2
O3= -6
What does a pH of 13 make a substance? Acidic or basic?
Basic
Does electronegativity increase or decrease moving across a period(left to right)?
Increases
Balance the equation.
NO + H2O ➡ NH3 + O2
4NO + 6H2O ➡ 4NH3 + 5O2
AB + C ➡ AC + B
Single Displacement
Assign each element an oxidation number
Pb(NO3)2
Pb= +2
N= +5
O= -2
O3= -6
What does red litmus paper turning blue in an aqueous solution mean?
The solution is basic.
Where do the least reactive metals go on the periodic table?
In group 18 on the far right side of periodic table, these elements are called noble gases.
Balance the equation.
C2H5OH + O2 ➡ CO2 + H2O
1C2H5OH + 3O2 ➡ 2CO2 + 3H2O
AB + CD ➡ AD + CB
Double Displacement
Assign each element an oxidation number.
Na2SO4
Na= +1
Na2= +2
S= +6
O= -2
O4= -8
How much more acidic is a pH of 2 than a pH of 5?
1,000x