C3.1 - Periodic Table Flashcards
How did Newlands arrange the first periodic table?
What was the property pattern he realised?
In order of increasing atomic mass
‘Law of Octaves’ - didn’t work for all elements
Give 2 ways Mendeleev re-arranged the periodic table
- Altered positions of some elements to match properties
- Left gaps for elements not yet discovered, and made predictions about them (these were later found to be true!)
What discovery let to the periodic table being rearranged to what it is now?
Discovery of protons
Now arranged in order of atomic number
What are 2 similarities between elements in the same group?
- Same number of outer shells
- Similar chemical properties
What is the same for all elements in the same period?
Number of electron shells in an atom
What group are the alkali metals?
Group 1
Name 4 properties of alkali metals, and how 3 of these properties change down the group
- Give +1 ions
- Low melt point (decreases)
- Soft (gets harder)
- Low density (increases)
What products are given when an alkali metal reacts with hydrochloric acid?
Why does the reactivity increase down the group?
Metal hydroxide + hydrogen gas
Outer electrons further from nucleus, so lost easier
Where are the transition metals found on the periodic table?
Between groups 2 and 3
Name 5 properties of transition metals
- Conduct heat and electricity
- High melting point
- Malleable (can be shaped)
- Ductile (can be cut into thin sheets without breaking)
- Good catalysts
Transition metals can have different charged ions. Why is this?
Electron shells can overlap -> different number of electrons in outer shell
What are the halogens?
Group 7
How do the properties of the halogens change down the group?
- Low boiling points increases down group
- Less reactive down group (gains electrons less easily)
- Goes from green gas (chlorine) to orange liquid (bromine) to grey solid (iodine) at room temperature
What type of ions do halogens react to make?
-1 ions
What happens when two different halogens are involved in a reaction?
More reactive halogen displaces less reactive halogen
