Element Groups & Properties

Question 1

Alkali Metals

Answer 1

• One valence electron
• Soft, metallic solids
• Shiny, lustrous
• Good conductors of heat and electricity
• Low densities, increasing with atomic mass
• Relatively low melting points, decreasing with atomic mass
• Vigorous exothermic reaction with water to reduce hydrogen, gas and an alkali metal hydroxide solution
• Ionize to lose their electron, to the ion has a +1 charged

Question 2

Alkaline Earth Metals

Answer 2

• Two valence electrons
• Metallic solids (harder than the alkali metals)
• Shiny, lustrous, oxidizes easily
• Good conductors of heat and electricity
• Denser than alkali metals
• Higher melting point than the alkali metals
• Exothermic reaction with water, increasing as you move down the group
• Ionize to lose valence electrons resulting in a +2 ion

Question 3

Metalloids

Answer 3

• Usually have a metallic luster
• Brittle
• Are usually considered semiconductors
• Have characteristics of both metals and nonmetals

Question 4

Nonmetals

Answer 4

• Brittle
• Low melting points
• Poor conductors of both heat and electricity (except for graphite)
• No luster, so they appear dull
• High electronegativity
• High ionization energy
• Hydrogen is often put in this group

Question 5

Halogens

Answer 5

• Seven valence electrons
• Highly reactive
• High electronegativity
• Decreased reactivity as you move down the column
• Physical state variation (fluorine and chlorine are gases and bromine and iodine are liquids)
• Poor conductors of both heat and electricity

Question 6

Noble Gases

Answer 6

• Full valence shell
• Low boiling and melting points
• Monatomic
• Non-flammable
• Poor conductors of heat
• Very low reactivity

Question 7

Transition Metals

Answer 7

• Number of valence electron is typically two, but it can vary in compounds
• Hard metallic solids
• Shiny and lustrous
• Good conductors of heat and electricity
• Denser than
• High melting points
• They are large atoms that have a range of oxidation states

Question 8

Post-Transition Metals

Answer 8

• Soft and malleable metals
• Low melting points
• Poor mechanical strength
• Good conductors of heat and electricity
• Fairly high density
• Used materials synthesis

Question 9

Lanthanides

Answer 9

• Silvery-white, lustrous metals
• Relatively soft metals, with increasing hardness as you move across the series
• Highly reactive, readily react with air and water to make hydrogen gas
• Most commonly oxidized to a +3 state
• As you move across the series, atomic radius decreases due to increased nuclear charge

Question 10

Actinides

Answer 10

• Radioactive
• Highly electropositive
• Pyrophoric - that is, when they are powdered finely, they spontaneously ignite in air
• Very dense metals
• Most are silvery
• They have multiple allotropes