Which change occurs when an atom in an excited

state returns to the ground state?

(1) Energy is emitted.

(2) Energy is absorbed.

(3) The number of electrons decreases.

(4) The number of electrons increases.

Which subatomic particles contribute to an atom's mass number but not its atomic number?

What is the difference between periods and groups on the periodic table?

How the moon surface is visible to an observer on earth

Which is a drawback to using incineration to dispose of toxic materials?

What formula equation represents the burning of sulfur to produce sulfur dioxide

Complete the following statements about the functions of the digestive system. The starts an involuntary swallowing action when it senses food. The squeezes food down the digestive tract by an involuntary synchronized muscle movement called.

How do you preform water displacement

Which bond or interaction would be most difficult to disrupt when compounds are placed into water?

Which of the following is the correct name for the compound hgs? mercury sulfide mercury (i) sulfide mercury (ii) sulfide mercury monosulfide?

Which of these has the most impact on the apparent brightness of a star seen from Earth? Gravitational pull, temperature of star, distance from earth, earths orbital pattern