Unit 8 - The Periodic Table Flashcards
Arrangement of elements in the periodic table
Arranged by atomic number
Amount of elements in the periodic table
118 - 94 occur naturally
Groups
The columns of the periodic table
Periods
The rows of the periodic table
Number of groups in the periodic table
8
Features of elements on the periodic table
Nucleon number and proton number
Properties of metals in the periodic table
- Large atomic radius
- Conduct heat and electricity
- Have a range of melting point values
- Malleable and ductile
- Shiny
Properties of non-metals in the periodic table
- Smaller atomic radius
- Do not conduct heat or electricity
- Generally low melting point values
- Brittle
- Dull
Metalloids
Elements that display properties of both metals and non-metals - found in the middle of the periodic table
Trends in groups of the periodic table
All elements in the same group have the same number of electrons in their outer shell
Relationship with have the same number of electrons on the outer shell
Elements with the same number of outer shell electrons react similarly
Period number relationship in the periodic table
The period number shows how many shells an element has
Group number relationship in the periodic table
The group number shows how many electrons are on the outer shell of the elements
Metal atoms relationship with ions
Metal atoms lose electrons and form positively charged ions
Non-metal atoms relationship with ions
Non-metal atoms gain electrons to form negatively charged ions
Groups and ion charges
- Group 1 = 1+
- Group 2 = 2+
- Group 3 = 3+
- Group 4 = N/A
- Group 5 = 3-
- Group 6 = 2-
- Group 7 = 1-
- Group 8 = 0
Covalent radius
Measure of how large individual atoms are
Relationship with covalent radius and the periodic table
- Increases as you go down a group
- Decreases as you go across a period
Group 1 metals name
The alkali metals
Elements in group 1
Lithium, Sodium, Potassium, Rubidium, Caesium, Francium
Chemical properties of Group 1 metals
- Reactivity increases down the group
- Density increases down the group
- Melting point decreases down the group
- Reacts more vigorously with water down the group
Lithium and water reaction
- Happens on the surface of the water
- Hydrogen gas given off
- Effervescence can be seen
- Lithium moves around on the surface
- Water will become alkaline
Lithium + water equation
- Lithium + Water –> Lithium hydroxide + Hydrogen
- 2Na(s) + 2H2O(l) –> 2NaOH(aq) + H2(g)
Sodium and water reaction
- Reaction is more vigorous than Lithium
- Heat given off
- Metal moves on the surface of the water faster
Sodium + water equation
- Sodium + water –> Sodium hydroxide + hydrogen
- 2Na(s) + 2H2O(l) –> 2NaOH(aq) + H2(g)
Potassium and water reaction
- Enough heat to ignite the hydrogen gas
- Lilac flame
- Potassium hops around the surface of the water
Potassium + water equation
- Potassium + Water –> Potassium hydroxide + Hydrogen
- 2K(s) + 2H2O(l) –> 2KOH(aq) + H2(g)
Reason for increasing reactivity
More shells leads to a higher atomic radius, losing less traction with the nucleus and causing the electron to be easier to lose
Name of Group VII elements
The Halogens
Features of halogens
- Non-metals
- Diatomic molecules
Colors of elements in Group VII
- Chlorine - Yellow-green gas
- Bromine - Red-Brown liquid
- Iodine - Dark purple solid
- Increasing darkness
Trends of The Halogens down the group
- Increasing darkness
- Increasing density
- Melting point increases
- Reactivity decreases
Reasons for decreasing reactivity
The ability to attract an extra electron on more outer shells weakens
Features of transition elements
- High densities
- High melting points - except for Mercury
- Not very reactive
- Don’t react rapidly with air or water
- very stable
- Form colored compounds
- Variable oxidation numbers
Uses of transition metals
- Jewelry
- catalysts e.g. iron to make ammonia
Variable oxidation state
An element can form different ions by losing a different number of electrons e..g Iron(II) or Iron(III)
Name for group VIII elements
The noble gases
Noble Gases
Helium, Neon, Argon, Krypton, Xenon, Radon, Oganesson
Features of noble gases
- Colorless gases
- Monatomic
- Complete outer shells
- Inert - not reactive
Trends of noble gases down the group
- Boiling point decreases
- Density increases
