Atomic Structure Flashcards
Define relative atomic mass
The weighted mean mass of an atom of an element compared to the mass of 1/12 of the mass of atom in carbon 12
Define relative isotopic mass
The mass of an atom of an isotope compared to the mass of 1/12 of the mass of an atom in carbon 12
Define first ionisation energy
The energy required to remove one mole of electrons from each atom in one mole of gaseous atoms to form one mole of gaseous 1+ ions
As each electron is removed from an atom, the remaining ion becomes more positively charged, thus doing what to the next ionisation energy?
Increasing it
What is the general trend in first ionisation energy across a period and why?
It increases.
Nuclear charge increases
Shielding stays the same
Atomic radii decreases
Attraction between outermost electrons and nucleus increases
What is the trend of first ionisation energy down a group?
It decreases.
Shielding increases
Increase in shielding outweighs increase in nuclear charge
Atomic radii increases
Attraction between outermost electrons to nucleus decreases
What is the trend in atomic radii across a period and why?
It decreases.
Nuclear charge increases
Shielding remains the same
Greater force of attraction between outermost electrons and nucleus
Less distance between them
What is the trend in atomic radii down a group and why?
It increases.
More energy levels
More shielding
Increase in nuclear charge outweighed by increase in shielding
Less attraction between outermost electrons and nucleus
More distance between them
How does the ionic radii of a positive ion compare to their corresponding atomic radii?
Smaller as it has less electrons and thus less repulsion
How does the ionic radii of a negative ion compare to their corresponding atomic radii?
Bigger as it has more electrons and thus repulstion
In an isoelectronic series, the ionic radius decreases as
atomic number increases
Define atomic radii
Half the distance between the 2 nuclei of a pair of covalently bonded atoms
