Question

exam 1
question 1: standard c.pm.1
match the term to the definition below:
the basic unit of a chemical element
a. electron
b. proton
c. compound
d. atom

question 2: standard c.pm.1
match the term to the definition below:
a substance that cannot be broken down into simpler substances by chemical means
a. element
b. atom
c. neutron
d. compound

question 3: standard c.pm.1
match the term to the definition below:
a chemical substance composed of many identical molecules containing atoms from more than one chemical element held together by chemical bonds
a. atom
b. compound
c. electron
d. neutron

question 4: standard c.pm.1
which scientist proposed atomic theory?
a. bohr
b. thomson
c. dalton
d. rutherford

question 5: standard c.pm.1
which scientist discovered protons?
a. bohr
b. thomson
c. dalton
d. rutherford

Explanation:

1. The basic unit of a chemical element is an atom; electrons and protons are subatomic particles, and a compound is made of multiple elements.
2. An element is a pure substance that cannot be broken down into simpler substances chemically; atoms are the units of elements, neutrons are subatomic, and compounds are combinations of elements.
3. A compound is a substance made of molecules with atoms from multiple elements bonded together; atoms are single element units, electrons/neutrons are subatomic.
4. John Dalton proposed the modern atomic theory; Bohr, Thomson, and Rutherford expanded on atomic structure later.
5. Ernest Rutherford discovered protons through his gold foil experiment and related research; Bohr focused on electron shells, Thomson discovered electrons, and Dalton proposed atomic theory without knowing subatomic particles.

Answer:

1. d. Atom
2. a. Element
3. b. Compound
4. c. Dalton
5. d. Rutherford