As atomic number increases atomic radii also increase down group 1. ionisation energy down group 1 will also decrease because as atomic radii gets bigger there is less electrostatic force between nuclei and electrons so less energy needed to remove valence electron.
Buffers in the human body can help to prevent a deadly change in blood pH.
I am pretty sure that the statement which is true is A. a molecule having a covalent bond can be ionic. I choose this option because you usually ca see how electons of polyatomic ions are being covalenr and gain or loose ionic electrons in order to accomplish the octet.<span>
</span>Do hope you find it helpful! Regards.
Alcohol is a pure substance
it is c. ionic compound just because it says ionic. can't be a crystal since there's no links to an ionic bond connected to crystals (and if it were it'd depend on the elements and the thingy majig itself right) and a covalent bond is an entirely different bond which isn't related to ionic. hope this helped, and i hope you have a good day too! :D