Question

true/false. write t if the statement is true and f if the statement is false.

1. the atom is the fundamental building block of everything we hear, feel, see, and experience.
2. john dalton was the first person recorded as thinking that matter was ultimately composed of atoms.
3. you can continually divide matter into smaller and smaller pieces without ever coming to an end.
4. ernest rutherford proved the existence of electrons.
5. the nucleus of an atom is a very small, dense region that contains over 99.9% of the atomic mass.
6. a positive charge attracts negative charges and repels other positive charges.
7. if two atoms each contain different numbers of protons, the atoms must be from different elements.
8. the atomic number of nitrogen is 14.01.
9. mendeleevs early periodic table predicted the existence of elements that had yet to be discovered.
10. group 2a elements are called alkali metals.

multiple choice. choose the one alternative that best completes the statement or answers the question.

1. which of the following is not part of daltons atomic theory?

a) atoms combine in simple, whole - number ratios to form compounds.
b) each element is composed of tiny indestructible particles called atoms.
c) most of the atoms mass and all of its positive charge is contained in a small core called the nucleus.
d) all atoms of a given element have the same mass and other properties that distinguish them from the atoms of other elements.
e) all of the above are part of the atomic theory.

1. which statement reflects the results of rutherfords gold foil experiments?

a) many alpha particles were deflected while passing through the foil.
b) most all of the alpha particles passed directly through the foil.
c) most all of the alpha particles were deflected back in the direction from which they came.
d) many alpha particles sputtered gold atoms off of the surface of the foil.
e) none of the above

Explanation:

1. Atoms are the fundamental building - blocks of matter we interact with, so it's true.
2. Democritus was among the first to think matter was composed of atoms, not John Dalton, so it's false.
3. Matter is composed of atoms and cannot be divided infinitely, so it's false.
4. J.J. Thomson discovered electrons, not Ernest Rutherford, so it's false.
5. The nucleus contains over 99.9% of the atomic mass, so it's true.
6. Opposite charges attract and like charges repel, so it's true.
7. The number of protons determines the element, so it's true.
8. The atomic number of nitrogen is 7, 14.01 is its atomic mass, so it's false.
9. Mendeleev's periodic table predicted undiscovered elements, so it's true.
10. Group 1A elements are alkali metals, Group 2A are alkaline - earth metals, so it's false.
11. The idea that most of the atom's mass and positive charge is in the nucleus is part of Rutherford's model, not Dalton's, so C is the answer.
12. In Rutherford's gold - foil experiment, most alpha particles passed directly through the foil, so B is the answer.

Answer:

1. T
2. F
3. F
4. F
5. T
6. T
7. T
8. F
9. T
10. F
11. C. Most of the atom's mass and all of its positive charge is contained in a small core called the nucleus.
12. B. Most all of the alpha particles passed directly through the foil.