Combined Foundation Flashcards
How is the modern periodic table ordered?
by atomic number
How were the early lists of the elements ordered?
by atomic mass
Why did Mendeleev swap the order of some elements?
To keep elements with similar properties together
Why did Mendeleev leave gaps in the periodic table?
to leave space for elements that hadn’t been discovered yet
Why do elements in a group have similar chemical properties?
they have the same number of electrons in their outer shell
Where are metals and non metals located on the periodic table?
Metals - left,
non-metals - right
What name is given to the group 1 elements?
alkali metals
Why are the alkali metals named this?
they react with water to form an alkali (a metal hydroxide)
Give the general equations for the reactions of alkali metals with oxygen, chlorine, and water?
metal + Oxygen -> metal oxide
metal + chlorine -> metal chloride
metal + water -. metal hydroxide + hydrogen
how does the reactivity of the alkali metals change down the group?
increases (get more reactive)
why does the reactivity of the alkali. metals increase down the group?
The atoms get bigger
the outermost electron gets further away from the nucleus
so there is a weaker electrostatic force of attraction
there is more shielding
and therefore it is EASIER to LOSE an electron.
What name is given to the group 7 elements?
halogens
Give the formula of the first four halogens?
F2, Cl2, Br2 and I2
How does the melting point of the halogens change down the group?
it increases
How does the reactivity of the halogens change down the group
the reactivity decreases
