Question

4.2 structure of the nuclear atom ( & electrons in atoms) review
section review
objectives
identify three types of subatomic particles
describe the structure of atoms according to the rutherford model
vocabulary
electrons
cathode ray
protons
neutrons
nucleus
part a completion
use this completion exercise to check your understanding of the concepts and terms that are introduced in this section. each blank can be completed with a term, short phrase, or number.
dalton theorized that atoms are indivisible, but the discovery of 1 particles changed this theory. scientists now know that atoms are made up of electrons, which have a 2 charge; 3 , which have a positive charge; and 4 , which are neutral. the latter two particles are found in the 5 of the atom. it was 6 who discovered the nucleus of the atom. the nucleus, which has a 7 charge, occupies a very small volume of the atom. in contrast, the negatively charged 8 occupy most of the volume of the atom.
part b true - false
classify each of these statements as always true, at; sometimes true, st; or never true, nt.

1. according to dalton’s atomic theory, atoms are composed of protons, electrons, and neutrons.
2. atoms of elements are electrically neutral.

Explanation:

Step1: Recall atomic theory history

Dalton thought atoms were indivisible, but sub - atomic particles discovery changed this. The first sub - atomic particle discovered was the electron. So, the answer to 1 is "sub - atomic".

Step2: Recall electron charge

Electrons have a negative charge, so the answer to 2 is "negative".

Step3: Recall positively charged particle

Protons are positively charged particles in an atom, so the answer to 3 is "protons".

Step4: Recall neutral particle

Neutrons are neutral particles in an atom, so the answer to 4 is "neutrons".

Step5: Recall location of protons and neutrons

Protons and neutrons are found in the nucleus of the atom, so the answer to 5 is "nucleus".

Step6: Recall nucleus discoverer

Ernest Rutherford discovered the nucleus of the atom, so the answer to 6 is "Rutherford".

Step7: Recall nucleus charge

The nucleus has a positive charge due to the presence of protons, so the answer to 7 is "positive".

Step8: Recall volume - occupying particles

Negatively charged electrons occupy most of the volume of the atom, so the answer to 8 is "electrons".

Step9: Evaluate Dalton's atomic theory statement

Dalton's atomic theory stated that atoms were indivisible and did not know about protons, electrons, and neutrons. So the statement "According to Dalton’s atomic theory, atoms are composed of protons, electrons, and neutrons" is never true (NT).

Step10: Evaluate atom neutrality statement

Atoms of elements are electrically neutral because the number of protons (positive charge) is equal to the number of electrons (negative charge). So the statement "Atoms of elements are electrically neutral" is always true (AT).

Answer:

1. sub - atomic
2. negative
3. protons
4. neutrons
5. nucleus
6. Rutherford
7. positive
8. electrons
9. NT
10. AT