chapter 14: the periodic table Flashcards
how are the elements of the periodic table arranged
in increasing proton number
What are horizontal rows of elements in the periodic table called?
periods
what are vertical columns of elements in the periodic table called?
groups
What are elements close to the ‘zig-zag’ line called?
metalloids
name the metalloids
(7 of them)
boron
silicon
germanium
arsenic
antimony
tellurium
polonium
what are the properties of metals
- high melting and boiling points
- shiny
- ductile, malleable
- sonorous
- good conductors of heat and electricity
what are the properties of metalloids
it has properties of metals and non-metals
what are the properties of non-metals
- gaseous or volatile
liquid or dull, brittle solids - low melting points
- poor conductors of heat and electricity
why is there an increase in metallic character with increasing atomic size?
as the valence electrons are further away from the nucleus, the elements have a greater tendency to lose the valence electron to form positive ions
period number = number of _______ _______
electron shells
group number = number of ________ _________
valence electrons
elements on the same group have similar ______________
chemical properties
physical properties of group 1 metals
(alkali metals)
I
- shiny and soft
- very good conductor of heat and electricity
- low melting and boiling points (decreases down the group)
- low density (decreases down the group)
chemical properties of group 1 metals
- alkali metals are highly reactive. to prevent them from reacting with air or water, they are stored under oil.
why are group 1 metals very chemically reactive?
they are all very chemically reactive as they all just have one electron in their outermost shell and therefore form M+ ions (Li+, Na+, K+). As we go down group 1, the reactivity of the alkali metals increases as it becomes easier to lose their outermost electron.
physical properties of group 7 elements
(halogens)
VII
- coloured (becomes darker down the group)
- low melting and boiling points (increases down the group)
Flourine
- appearance
- melting point
- boiling point
- state at r.t.p.
- pale yellow
- melting: -220
- boiling: -188
- rtp state: gas
Chlorine
- appearance
- melting point
- boiling point
- state at r.t.p.
- greenish-yellow
- melting: -101
- boiling: -34
- rtp state: gas
Bromine
- appearance
- melting point
- boiling point
- state at r.t.p.
- reddish-brown
- melting: -7
- boiling: 59
- rtp state: liquid
Iodine
- appearance
- melting point
- boiling point
- state at r.t.p.
- shiny-black / purplish black
- melting: 114
- boiling: 184
- rtp state: solid
Lithium reaction with water
reacts quickly. the metal floats on the surface of water
no flame observed
2Li (s) + 2H2O (l) –> 2LiOH (aq) + H2 (g)
Alkali metals react vigorously with water to form ………
the alkaline hydroxide and liberating hydrogen gas
Sodium reaction with water
reacts violently. the metal darts around the water surface. reaction may be explosive.
hydrogen gas catches fire and burns with a yellow fire.
2Na (s) + 2H2O (l) –> 2NaOH (aq) + H2 (g)
Potassium reaction with water
reacts very violently. the metal darts about the water surface. reaction is explosive.
hydrogen gas catches fire and burns with a lilac flame
2K (s) + 2H2O (l) –> 2KOH (aq) + H2 (g)
