Unit 12- Periodic table Flashcards
How many electrons are there in the outer shell of group 3 elements?
3
Difference between group and period
Groups are column, periods are row.
Describe the trend in physical properties as you go down group 1 elements
Softness increases, density increases, melting point decreases
Describe the reaction between water and the first three group 1 elements (lithium, sodium, potassium)
Lithium floats and fizzes, sodium shoots across the water, potassium melts with the heat of the reaction.
State the trend in reactivity in group 1 elements
as you go down group 1 elements, reactivity increases.
Why do elements from same group react in a similar way
They have same number of electron in the most outer shell.
Why are group 1 elements so reactive
They only need to lose one electron to gain full outer shell, so they have a stronger drive to react. So they will lose electron and become ion
Describe physical properties of group 1 elements
Good conductor of heat and electricity, softer than other metals, low density, low melting and boiling point compare to other metals.
What’s another term to call group 7 elements
halogens
Are halogens poisonous
yes
Describe the trend of physical properties in group 7
As you go down group 7 elements, colour gets darker, density increases, boiling point increases
Describe the trend of chemical properties in group 7
AS you go down group 7 elements, reactivity decreases.
Explain why are group 7 elements so reactive
They only need to gain one electron to gain full outer shell, so they have a stronger drive to react. So they will gain electron and become ion
How the halogens react with halides
A halogen will displace a less reactive halogen from a solution of its halide( group 7 compound)
Why is group 8 elements not reactive
They have a stable full outer shell
Trends in physical properties for group 8 elements
increase in size and mass, density increases, boiling point increases
Use of helium
fill ballons and airship
Use of argon
protect metals that are being welded, filler in tungsten light bulbs
Use of neon
used in advertising signs
Use of krypton
used in lasers
Use of xenon
lighthouse lamp
State physical properties of transition elements
hard, strong, high melting point, malleable, ductile, good conductors of the heat of electricity, high density
State chemical properties of transition elements
less reactive than group 1 metals, variable oxidation states, form coloured compounds, can form complex ions
Uses of transition elements
catalysts, making alloys, used in building structures
Trends across period 3
nu,ber of valency increases by 1 each time, melting and boiling point rises to the middle of the period then fall back as you go right
What are metalloids and give example
elements that behave like metal in some ways but also behave like non-metal. For example, Silicon
What is semi-conductor
only conducts electricity when temperature is high
