EL 8 Flashcards
what is the alternative names for the following:
- Group 1
- Group 2
Group 1 - Alkali metals
Group 2 - Alkali earth metals
Describe and explain the trends in group 1 and 2
- They get more metallic going down the group. This is because form cations more readily going down the group in ionic compounds
- Elements become less metallic going across a period, because group 1 metals are more reactive than group 2 metals
why aren’t s-block metals as widely used as others
- they tend to be more soft and weak with low melting points
- they are too reactive with water and oxygen
what is the first ionisation enthalpy
The first ionisation enthalpy of an element is the energy needed to remove one electron from every atom in one mole of isolated gaseous atoms of the element
what is the general trend across a period for the first ionisation enthalpy
- it becomes more difficult to remove the outer electron going across a period
- this is because whilst electrons are being added to the outer shell protons are being added to the nucleus so the outer electros are more strongly attracted
how does ionisation energy provide support for the theory of electron subshells
- there is some variation amongst the general trend of increase across a period
- there is a decrease between beryllium and boron
- beryllium’s outer electron is in the s subshell and boron’s is in the p subshell
- s sub shell is lower energy than p
define acid
a compound that dissociates in water to produce hydrogen ions
define base
a compound that reacts with an acid - is a proton acceptor - to produce water (and salt)
define alkali
- a base that dissolves in water to produce hydroxide, OH - ions
what is a neutralisation reaction
- when an alkali reacts with an acid and a salt is formed
what does the concentration of a solution depend on
- the amount of solute
- the final volume of the solution
what’s the relationship between
- moles
- conc.
- volume
amount (moles) = concentration (mol/dm3) x volume of solution (dm3)
