1. which statement about subatomic particles is not true?
protons and electrons have opposite charges.
neutrons have no electrical charge.
protons and neutrons have the same charge.
protons and neutrons have nearly the same mass.
2.
which term describes the sum of the number of protons and neutrons in an atom?

mass number

nuclear charge

atomic charge

atomic number
3.
which is not part of john dalton’s atomic theory?

all elements are composed of atoms.

atoms are made up of smaller particles.

atoms of different elements have different masses.
4.
all atoms of the same element have the same mass.
dalton’s model of an atom is best described as

a scoop of chocolate chip ice cream

a solar system

a cloud

a solid sphere
5.
who provided the first evidence that atoms contain subatomic particles?

j. j. thomson

ernest rutherford

john dalton
6.
which statement about electrons and atomic orbitals is not true?

an atom’s lowest energy level has only one orbital.

an electron has the same amount of energy in all orbitals.

an electron cloud represents all the orbitals in an atom.

an orbital can contain a maximum of two electrons.
7.
how is heavy water different from normal water?

a hydrogen atom in heavy water has an extra proton.

a hydrogen atom in heavy water has an extra neutron.

an oxygen atom in heavy water has an extra neutron.

an oxygen atom in heavy water has an extra proton.
8.
what experimental evidence did thomson use to support his hypothesis that atoms are made up of even smaller, charged particles?

the glowing beam was always deflected by charged plates.

identical particles were produced no matter which metal he used.

the particles all had the same mass as a hydrogen atom.
9.
atoms may emit light energy when

electrons move to a higher energy level

protons move to a higher energy level

protons move to a lower energy level

electrons move to a lower energy level
10.
which term describes the region in which an electron is most likely to be found?

isotope

path

orbital

cloud
11.
according to dalton, if 2 grams of element x combine with 4 grams of element y to form compound xy, how many grams of element x would combine with 28 grams of element y to form the same compound?

28

14

7

56
12.
an electron is a particle with a

positive charge, found outside the nucleus

negative charge, found in the nucleus

positive charge, found in the nucleus

negative charge, found outside the nucleus
13.
the glow of a neon light is caused by electrons emitting energy as they

move from higher to lower energy levels

collide with the nucleus

move from lower to higher energy levels

collide with other electrons
14.
to find the number of neutrons in an atom, subtract its

atomic number from its mass number

mass number from its atomic number

isotope number from its atomic number
15.
which is the best analogy describing the location of an electron in an atomic orbital?

pins on a map plotting your location every minute of a school day

the path of a bee moving from flower to flower in a garden

free-thrown basketballs bouncing on a basketball court

1. Protons and neutrons have the same charge.

Protons have positive charge, equal to , while neutrons have zero charge.

2. mass number

The mass number of an atom is equal to the sum of protons and neutrons inside its nucleus.

3. Atoms are made up of smaller particles.

According to Dalton's theory, atoms are the smallest particles that make matter, and they are indivisible and indestructible, so they are NOT made up of smaller particles.

4. a solid sphere

In Dalton's theory, atoms are not made of smaller particles, so we can think them as solid spheres.

5. J. J. Thomson

In his experiment with cathode ray tubes, JJ Thomson demonstrated the existance of the electrons, which are negatively charged particles inside the atom. In his model of the atom (plum-pudding model), Thomson thought the atom consists of a uniform positive charge and the electrons are located inside this positive charge.

6. An electron has the same amount of energy in all orbitals.

In fact, each orbital corresponds to a different energy level: the farther the orbital from the nucleus, the higher the energy of the electrons contained in that orbital.

7. A hydrogen atom in heavy water has an extra neutron.

Heavy water is a type of water that contains deuterium, which is an isotope of the hydrogen consisting of one proton and one neutron (so, one extra neutron).

8. The glowing beam was always deflected by charged plates

In his cathode's ray tube experiment, Thomson shows that the beam of unknown particles (= the electrons) were deflected by charge plates, so the particles had to be also electrically charged.

9. electrons move to a lower energy level

When electrons move from a higher energy level to a lower energy, they emit a photon (light) of energy equal to the difference in energy between the two energy levels.

10. orbital

In quantum mechanics, electrons in the atom are not precisely located, since we cannot determine their exact position and velocity at the same time. Therefore, we can only describe regions of space where the electrons have a certain probability to be found, and these regions of space are called orbitals.

11. 14

According to Dalton's theory, the proportions of the reactants must be respected in order to form the same compound. Therefore, we can write:

12. negative charge, found outside the nucleus

Electrons are particles with negative charge of magnitude that orbit around the nucleus. The nucleus, instead, consists of protons (positively charged, with charge opposite to the electron) and neutrons (neutrally charged).

13. move from higher to lower energy levels

When electrons move from a higher energy level to a lower energy inside a neon atom, they emit a photon (which is light) whose energy is equal to the difference in energy between the two energy levels.

14. atomic number from its mass number

In fact:

- the atomic number of an atom (Z) is equal to the number of protons inside the nucleus

- the mass number of an atom (A) is equal to the sum of protons+neutrons inside the nucleus

Therefore, we can find the number of neutrons in the nucleus by calculating the difference between A and Z:

Number of neutrons = A - Z

15. None of them

None of these examples is a good analogy to describe the location of an electron in an atomic orbital: in fact, the position of an electron in an orbital cannot be precisely described, we can only describe the probability to find the electron in a certain position, and none of these example is an analogy of this model.

an obstruction