the periodic table Flashcards
(12 cards)
What did Newlands do
only 63 elements were discovered and he arranged elements in order of atomic weight
what did Mendeleev do
-left gaps for undiscovered elements
-elements were placed in vertical columns (groups) with similar properties
-organised elements in order of increasing protons
what are the properties of group 0 and what are they called
noble gasses:
-full outer shell
-boiling point increases down the group
why are group 0 elements unreactive
full outer shell of electrons
what are the properties of group 1 elements and what are they called
alkali metals:
-1 electron in their outermost shell
-low melting/boiling point, decrease down the group
-less density
Explain why the reactivity of elements changes going down Group 1
reactivity increases as u go down the group, the outer shell gets further away from the nucleus so there’s less reaction between the nucleus and the outer shell, so the atom loses an electron more easily
why are alkali metals stored in oil
they react vigorously with oxygen and water
what is formed when an alkali metal reacts with water
metal hydroxide + hydrogen
what is formed when a metal reacts with a non-metal
ionic compound
the metal atom looses 1 electron to form a metal ion with a positive charge
what are the properties of group 7 elements and what are they called
halogens:
-7 electrons in their outermost shell
-reactivity decrease down the group, outer shell gets further from the nucleus so its less easy to gain/ loose electrons
-melting/boiling point increases down the group
what is produced when halogens react with metals
ionic salts
halogen gains 1 electron to form a halide ion (- charge)
what are properties are transition mentals (group 2&3)
-form coloured compounds
-can be used at catalysts to speed up chemical reactions
- have ions of different charges
-high melting point
