2.6 Subatomic Particles: Protons, Neutrons, and Electrons in Atoms

Question 1

All atoms are composed of the same subatomic particles: ______, ______, and ______.

Answer 1

All atoms are composed of the same subatomic particles: protons, neutrons, and electrons.

Question 2

Protons and neutrons, as we saw earlier, have nearly identical ______

Answer 2

Protons and neutrons, as we saw earlier, have nearly identical masses

Question 3

A more common unit to express these ______ is the atomic mass unit (amu) , defined as 1/12 the mass of a carbon atom containing six protons and sixneutrons.

Answer 3

A more common unit to express these masses is the atomic mass unit (amu) , defined as 1>12 the mass of a carbon atom containing six protons and sixneutrons.

Question 4

The mass of a proton or neutron is approximately _ amu. Electrons, by contrast, have an almost negligible mass of 0.00091 * 10^-27 kg or 0.00055 amu.

Answer 4

The mass of a proton or neutron is approximately 1 amu. Electrons, by contrast, have an almost negligible mass of 0.00091 * 10^-27 kg or 0.00055 amu.

Question 5

The proton and the electron both have electrical ______.

Answer 5

The proton and the electron both have electrical charge .

Question 6

In atomic (or relative) units, the electron is assigned a charge of __ and the proton is assigned a charge of __

Answer 6

In atomic (or relative) units, the electron is assigned a charge of -1 and the proton is assigned a charge of +1

Question 7

Thecharge of the ______ and the ______ are equal in magnitude but opposite in sign, so that when the two particles are paired, the charges sum to zero. The neutron has no charge.

Answer 7

Thecharge of the proton and the electron are equal in magnitude but opposite in sign, so that when the two particles are paired, the charges sum to zero. The neutron has no charge.

Question 8

Matter is usually ______ -______ (it has no overall charge) because protons and electrons are normally ______ in equal numbers.

Answer 8

Matter is usually charge-neutral (it has no overall charge) because protons and e lectrons are normally present in equal numbers.

Question 9

When matter does acquire charge ______ , these imbalances usually equalize quickly, often in dramatic ways.

Answer 9

When matter does acquire charge imbalances, these imbalances usually equalize quickly, often in dramatic ways.

Question 10

A sample of matter—even a tiny sample, such as a sand grain—composed of only protons or only electrons, would have extraordinary ______ forces inherent within it and would be unstable

Answer 10

A sample of matter—even a tiny sample, such as a sand grain—composed of only protons or only electrons, would have extraordinary repulsive forces inherent within it and would be unstable

Question 11

Elements: Defined by Their Numbers of ______

Answer 11

Elements: Defined by Their Numbers of Protons

Question 12

f all atoms are composed of the same subatomic particles, what makes the atoms of one element different from those of another?

Answer 12

The answer is the number of these particles.

Question 13

The most important number to the identity of an atom is the ______ of ______ in its nucleus

Answer 13

The most important number to the identity of an atom is the number of protons in its nucleus

Question 14

The number of protons defines the ______.

Answer 14

The number of protons defines the element.

Question 15

For example, an atom with _ protons in its nucleus is a helium atom, an atom with _ protons in its nucleus is a carbon atom and an atom with _ protons in its nucleus is a uranium atom.

Answer 15

For example, an atom with 2protons in its nucleus is a helium atom, an atom with 6 protons in its nucleus is a carbon atom and an atom with 92 protons in its nucleus is a uranium atom.

Question 16

The number of protons in an atom’s nucleus is its ______ ______ and is given the symbol _ .

Answer 16

The number of protons in an atom’s nucleus is its atomic number and is given the symbol Z .

Question 17

the atomic numbers of known elements range from _ to _ (although additional elements may still be discovered), as shown in the periodic table of the elements

Answer 17

the atomic numbers of known elements range from 1 to 116 (although additional elements may still be discovered), as shown in the periodic table of the elements

Question 18

Each element, identified by its unique atomic number, is represented with a ______
______ symbol , a one- or two-letter abbreviation listed directly below its atomic number on the periodic table.

Answer 18

Each element, identified by its unique atomic number, is represented with a unique
chemical symbol , a one- or two-letter abbreviation listed directly below its atomic number on the periodic table.

Question 19

The chemical symbol and the atomic number always __ ____ .

Answer 19

The chemical symbol and the atomic number always go together.

Question 20

If the atomic number is 2, the chemical symbol must be __.

Answer 20

The chemical symbol and the atomic number always go together.