16.H2O (water) and NaCl (salt) are _________ that are in salt water, which is a(n) __________. Water and salt contain the ____________ hydrogen, oxygen, sodium, and chlorine.


Compounds; mixture; elements

Mixture; compounds; elements

Element; compounds; mixture

Compound; elements; compounds


12.The number of _____ determines which element it is.


electrons

protons

positrons

neutrons