C2 The periodic Table Flashcards
What are metals?
Elements which form positive ions when they react
Why do atoms react?
To form a full outer shell
This can be done by losing, gaining or sharing electrons
Why do metals react to form positive ions?
they lose electrons
They don’t have many electrons to remove
Electrons are far away from the nucleus so don’t require much energy to be removed
What are the properties of metals?
Strong
Malleable
Good conductors of heat and electricity
High boiling and melting points
What are the properties of nonmetals?
Dull looking
Brittle
Aren’t always solid at room temperature
Don‘t generally conduct electricity
Lower density
What do alkali metals react with water to produce?
A metal hydroxide
Hydrogen
What is a trend for alkali metals reacting with water?
The more reactive lower down the group
The amount of energy given out increases down the group
What do alkali metals react with chlorine to produce?
White metal salts
What is the trend for reactions of alkali metals with chlorine?
Reaction get some more vigourous down the group
What do reactions with alkali metals and oxygen produce?
Metal oxides
How do the properties of alkali metals differ to transition metals?
They are more reactive
Less dense, strong and hard
Low melting points
What are the properties of transition metals?
Typical of a metal
Good conductors, very dense, strong, shiny
What special properties are there of transition metals?
They can have more than one ion
They form coloured compounds
Often make good catalysts
How do halogens exist?
As diatomic molecules that are covalently bonded
What are the trends of group 7 elements?
Less reactive
Higher melting and boiling points
Higher relative atomic masses
Why do displacement reactions occur with halogens?
A more reactive halogen will replace the less reactive halogen in a salt
This is because a less reactive halogen gains an electron less easily. there is a greater distance from the nucleus to the electron and shielding from the internal energy levels.
What is a minus one ion of a halogen called?
Halide
What makes noble gases inert?
They all have full outer shells so are energetically stable
What are all group 0 elements at room temperature?
Colourless gases
How do all group 0 elements exist (what type of molecule)?
Monatomic gases
Will noble gases set on fire?
No as they are inert
What is the trend for boiling points of the noble gases?
They increase as you go down the group
Why do the boiling point of noble gases increase down the group?
There is an increase in the number of electrons in the atom which means there is greater intermolecular forces
what value tells you which group an element is in?
the number of electrons on the outer shell
how many electrons do elements in group 0 have on their outer shell?
a full outer shell (8 or 2)
why do elements in the same group react in a similar way?
they each have the same number of electrons on the outer energy level
what are Dobereiner’s Triads?
elements with similar chemical properties often occur in threes
what are Newlands’ octaves?
if the elements were placed in order of atomic weight, every eighth element had similar chemical properties
what did Mendeleev do with his periodic table that no one had done before?
switch specific elements so they fitted with the properties of other elements
leave gaps where elements had not been discovered
what are some differences between Mendeleev’s periodic table and the modern one?
Today, the periodic table is ordered by atomic number rather than atomic weight and group 0 is present.
what is the trend for reactions of the alkali metals?
they react more rapidly as you go down the group as the outer electron is more easily lost.
this is because the electron is less attracted to the positive nucleus as there is a greater distance between the two.
the outer electron is also shielded by the internal energy levels
what do halogens form when they react with non-metals?
covalently bonded compounds
what do halogens form when they react with metals?
ionic compounds
