Tell me its urgent plz

Nacl

Explanation:

Because there is no such thing as a chemical/element with a lower case symbol

KBr potassium bromine

l hope it's helps

explanation:

i think option no d is the correct answer

the density(ratio between mass and volume as m/v) decreases from top to bottom in periodic table group as the size increases and nuclear charge decreases. but in periods density increases from left to right as atom size decreases and nuclear charge increases.