Which of the following describes the properties of a substance?
A. All of these
B. How it reacts with other chemicals.
C. How it looks.
D. How it behaves.

An electron moved from shell n = 2 to shell n = 1. what most likely happened during the transition? a fraction of a photon was added. a photon of energy was absorbed. a fraction of a photon was removed. a photon of energy was released.

Which metal exist in liquid state and can be cut with knife ?

An atom of lithium-7 has an equal number of(1) electrons and neutrons(2) electrons and protons(3) positrons and neutrons(4) positrons and protons