C2 the periodic table Flashcards
how is the modern periodic table ordered
by atomic number
how were the early lists of elements ordered
by atomic mass
why did mendeleev swap the order of some elements
to group them by their chemical properties
why did mendeleev leave gaps in his periodic table
leave room for elements that had not yet been discovered
why do elements in a group have similar chemical properties
have the same number of electrons in their outer shell
where are metals and non-metals located on the periodic table
metals to the left, non-metals to the right
what name is given to the group 1 elements
alkali metals
why are the alkali metals named this
they are metals that react with water to form an alkali
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 (more reactive)
why does the reactivity of the alkali metals increase down the group
they are larger atoms, so the outermost electron is further from the nucleus, meaning there are weaker electrostatic forces of attraction and more shielding between the nucleus and outer electron, and it is easier to lose the electron
what is the name given to group 7 elements
halogens
give the formulae of the first four halogens
F2,Cl2,Br2,I2 (the 2s are meant to be little)
how do the melting points of the halogens change down the group
increase (higher melting points)
how does the reactivity of the halogens change down the group
decrease (less reactive)
