Physical Science Exam: Chapter 4

Who provided evidence for the existence of a nucleus in an atom?

Ernest Rutherford

All isotopes of the same element have the same mass number

False

All subatomic particles have the same mass

False

An isotope is an atom that has lost protons

False

In an atom the atomic number, the number of protons and the number of neutrons are always the same

False

James Chadwick discovered electrons

False

Most of the mass of an atom is located in the electron cloud

False

Protons and electrons are located in the nucleus

False

A proton has a mass of 1 AMU

True

An atom of one element is different from an atom of another element because of its atomic number

True

An ion is an atom that has gained or lost an electron

True

If an ion has lost electron its charge will be positive

True

The overall charge of an atom is neutral, because it has the same number of electrons and protons

True

Which of the following is NOT part of John Dalton's atomic theory? a. Atoms contain subatomic particles b. All elements are composed of atoms c. A compound contains atoms of more than one element d. All atoms of the same element have the same mass

a. Atoms contain subatomic particles

Which statement about subatomic particles is NOT true? a. Protons and neutrons have the same charge b. Protons and neutrons have almost the same mass c. Protons and electrons have opposite charges. d. Unlike protons and electrons, neutrons have no charge

a. Protons and neutrons have the same charge

Which of the following is unique for any given element? a. the number of protons b. the mass of a neutron c. the charge on the electrons d. the number of neutrons

a. the number of protons

The Greek philosopher Democritus coined what word for a tiny piece of matter that cannot be divided?

atom

The number of protons in one atom of an element is that element's

atomic number

To find the number of neutrons in an atom, you would subtract

atomic number from mass number

Which statement about subatomic particles is true? a. Neutrons have no charge and no mass b. Protons, neutrons, and electrons all have about the same mass c. An electron has far less mass than either a proton or neutron d. Unlike protons or neutrons, electrons have no mass.

c. An electron has far less mass than either a proton or neutron

Rutherford's gold foil experiment provided evidence for which of the following statements? a. Alpha particles have a positive charge b. Negative and positive charges are spread evenly throughout an atom c. There is a dense, positively charged mass in the center of an atom d. Gold is not as dense as previously thought

c. There is a dense, positively charged mass in the center of an atom

Which statement is true about oxygen-17 and oxygen-18? a. Their atoms have an identical mass b. The have the same mass number c. They are isotopes of oxygen d. They do not have the same number of protons

c. They are isotopes of oxygen

J. J. Thomson's experiments provided evidence that an atom

contains negatively charged particles

Which of the following most accurately represents John Dalton's model of the atom? a. a hollow sphere with a dense nucleus b. a tiny, solid sphere with an unpredictable mass for a given element c. a sphere that is hollow throughout d. a tiny, solid sphere with a predictable mass for a given element

d. a tiny, solid sphere with a predictable mass for a given element

Which subatomic particle has a negative charge?

electron

In Niels Bohr's model of the atom, electrons move

like planets orbiting the sun

Democritus thought that matter was made of tiny particles

that could not be divided

What does the electron cloud model describe?

the most likely locations of electrons in atoms

According to John Dalton's observations, when elements combine in a compound,

the ratio of their masses is always the same