Unit 4 - The Periodic Table - Introduction & Groups - Regents Flashcards
Why is the Periodic Table used?
Determines how chemicals will react or behave
Who was Dmitri Mendeleev? (5)
- Arranged elements by increasing X
- First usable PT
- Noticed elements w/ similar chem & phys prop.
- Identified regular, predictable & periodic intervals of properties
- Predicted existence of elements not yet discovered (boron & silicon)
(X = atomic mass)
How was the atomic number discovered? (3)
- Henry Moseley (student of Rutherford)
- Used X - Rays
- Repositioned elements on modern PT
What are Groups? (4)
- Vertical Columns
- Same Group = Same VE
- Same group = Same Reaction & Bonding (VE)
- Similar properties
Group 15 = 5 VE
Group 2 = 2 VE
Group 18 = 8 VE (except He)
What are Periods? (2)
- 7 Horizontal Rows
- Period Num. = Num. of Principle EL
What are alkali metals? (3)
- Group 1
- Not found free in nature
- Because it is the most reactive metals
What are Alkaline Earth Metals? (3)
- Group 2
- High reactive (less than G1)
- Found in rocks on Earth’s crust
What are Transition Metals? (5)
- Group 3 - 12
- Form Colored Solutions
- Don’t form normal rules of VE
- Good conductors of electricity
- Malleable & Ductile
Definition of Malleable
Easily bended/hammered
Definition of Ductile
Stretched into a thin wire without breaking
Ex: Copper, often used in electrical wiring
What are Lanthanides (La) & Actinides (Ac)? (2)
- Two rows at the bottom of the PT
- Rare earth metals
What are non - metals? (4)
Location, Properties, Form
- Fount on the right side of the PT
- Brittle, Solid or Gases (Bromine is liquid)
- Form ions of a negative charge
- Don’t Conduct Electricity
What are Halogens? (3)
- Group 17
- Most reactive nonmetals
- Most are poisonous
What are Noble Gases? (4)
- Group 18
- Full outer Valence Shell (8)
- Unreactive
- Gases at room temp.
Definition of Families (2)
- 1 or several groups
- Share physical and chemical properties
What are some information of Hydrogen? (3)
- Family of its own
- Diatomic & Reactive Gas
- Promising for alternative fuel for auto
What are metals? (4)
- 75% of Elements
- Found on the left of PT
- Solid at Room Temp.
- Exception = Mercury
What are 6 physical and chemical properties of metals?
- Malleable
- Luster
- Ductile
- Conductors of Heat & Electricity
- Positive Ions
- Reactive
What is it meant by “reactive”?
Can easily form compounds with other elements
What are Allotropes? (2)
- Same Elements
- Differ in molecular or crystal structure
Ex:
Oxygen (O2) and Ozone (O3)
Graphite (weak bonds) vs. Diamond (network solid) vs. Graphene
What types of ions do metals and nonmetals form?
Metals: Cations (+)
Nonmetals: Anions (-)
Definition of Atomic Radius
1/2 the distance between nuclei of 2 adjacent atoms
What happens to the atomic radius from left to right on the PT? (4)
- Atomic Radius decreases
- Greater protons:electrons ratio
- Greater Nuclear Pull
- Pulling e- closer to the nucleus
What happens to the atomic radius from top to bottom on the PT? (3)
- Atomic Radius Increases
- More Principal Energy Levels
- VE Shells will be farther away from the nucleus
How does the Ionic Radius of metals differ from nonmetals? (size of METALS in comparison) (5)
- Metals have a smaller radius
- Forms cations (less e-, and + charge)
- To achieve the full VE shell (8)
- Higher nuclear pull over electro. rep.
- Electrons get closer to the nucleus
How does the Ionic Radius of nonmetals differ from metals? (size of NONMETALS in comparison) (5)
- Nonmetals have a larger radius
- Forms anions (more e-, and - charge)
- To achieve the full VE shell (8)
- Lower nuclear pull over electro. rep.
- Electrons DO NOT get closer to the nucleus
Do metals or nonmetals tend to lose e- more easily?
Metals, because it has lower ionization energy.
When the atomic radius DECREASES, what does this mean about the likelihood of losing electrons? Do the elements become more or less metallic?
- e- is closer to nucleus
- e- is more attracted & held tightly
- Less likely for it to get lost
- Less metallic (metals lose more e-)
When the atomic radius INCREASES, what does this mean about the likelihood of losing electrons? Do the elements become more or less metallic?
- e- is farther to nucleus
- e- is less attracted & loose
- More likely for it to get lost
- More metallic (metals lose more e-)
Where are metals located on the PT and where are nonmetals located on the PT?
Metals: Bottom Left
Nonmetals: Upper Right
What is the largest, most metallic and lowest ionization energy element?
Francium
What is electronegativity? (3)
- Measure of an atom’s
- Attraction of e-
- When bonded to another atom
Where on the periodic table does electronegativity INCREASE, left or right? (3)
- Right
- Number of protons increase
- Increasing the positivity & attraction of e-
Where on the periodic table does electronegativity DECREASE, bottom or top? (4)
- Bottom
- Principle energy levels increase
- VE is farther from the nucleus
- Reducing nuclear pull & attraction of e-
What is the most electronegative element? (5)
- Fluorine
- Located on the top right
- Although Helium is farthest top and right
- It’s a noble gas
- Isn’t motivated to attract e-
What is Ionization Energy?
- Energy required
- To remove the outermost e-
- From the atom
How does the atomic radius relate to the Ionization Energy?
- Large Atoms - Low ionization energy
- e- is farther from the nuclear pull
- Small Atoms - High ionization energy
What element can be found free in the environment?
Gold (Au)
What is meant when an element is active?
It is highly reactive to form compounds, like Alkali Metals (G1) and Halogens (G17)
What are metalloids? (3)
- Found by the steps (Al is not a metalloids)
- Have both metal & non metal characteristics
- Semiconductors
