Periodicity Flashcards
Define core charge
a measure of the attractive force between valence electrons of an atom and the nucleus. Larger core charge (larger atom), the weaker the electronegativity.
Define atomic radius
distance between the nucleus and valence electron(s).
Define electron configuration
similarities in electron arrangement (e.g. 1 valence e-) giving elements similar properties.
Define first ionisation energy
the energy required to remove each atom in one mole of gas, to form one mole of 1+ gas ions.
Define electronegativity
the tendency for an atom to attract a bonding electron pair.
Define electron affinity
attraction of an atom (gaseous state) for an electron, how much does it want electrons.
What is the trend of states of matter at room temperature in the periodic table?
Moving from left to right, elements change from solids to gases, with 2 liquids scattered between.
Trends in atomic radius, explain.
Across a period, atomic radii decreases due to core charge increasing and shells staying the same quantity but more valence electrons meaning higher electronegativity.
Down a group, atomic radius increases due to increase in shells resulting in higher shielding and lower electronegativity.
Trends in core charge, explain.
Across a period, core charge will increase as there is an increase in electronegativity.
Down a group, core charge will remain the same as number of protons is proportional to shielding electrons.
Trends in electronegativity, explain.
Across a period, electronegativity will increase as the number of shells stays the same but valence electrons increase, resulting in smaller atomic radius and charge in nucleus increases.
Down a group, electronegativity decreases as electron shielding increases due to more shells, greater atomic radius.
Trends in first ionisation, explain.
Across a period, first ionisation energy will increase as electronegativity is higher meaning more energy is required to remove valence electrons.
Down a period, first ionisation energy decreases as the valence electrons have lower electronegativity (not as attracted to nucleus) therefore need less energy to be removed.
Trend in elements with reactivity of water, explain.
Down a group, element will be more reactive as their first ionisation energy is less meaning they can lose or gain valence electrons easier due to higher electron shielding and larger atomic radius.
Define ionisation energy.
The energy required to remove an electron from a atom or molecule and make an ion.
Define second ionisation energy.
Energy required to remove one electron from each ion in one mole of gas, to form one mole of 2+ions.
Define succesive ionisation.
third ionisation process etc.
