PT Review Unit 2

The atomic number is

• The number of electrons in the nucleus

• The number of protons in the nucleus

• The number of neutrons in the nucleus

• The number of atoms in a mole

The first person to introduce the possibility of atoms making up all of nature was

• Democritus

• Chadwick

• Mendeleev

• Dalton

JJ Thomson was able to discover the electron through the use of what device?

• Cathode ray tube

• Alpha particle

• X-rays

• Gold foil

Which of the following is correct scientific notation for 12 369 000 000 000?

• 12.369 X 10^12

• 1.2369 X 10^13

• 1.2369 X 10^14

• 1.2369 X 10^{-13}

Two isotopes of an element have different

• Numbers of electrons

• Numbers of protons

• Atomic numbers

• Mass numbers

• 6 020 000

• 602 000 000

• 0.000 006 02

• 0.000 000 602

Rutherford’s gold foil experiment demonstrated that

• Electrons have a negative charge

• Alpha particles have a positive charge

• Most of the atom is empty space

• Electrons are orbiting around the nucleus

A reaction which releases heat is said to

• Be exothermic

• Be endothermic

• Be nonspontaneous

• None of the above

The number of protons in the nucleus of an atom of magnesium is (a)   .

• 6

• 12

• 14

• 18

Water freezing is an example of a (a)  

• Chemical change

• Physical change

• Chemical property

• Physical property