chapter 4 physical science

Which statement about subatomic particles is true?

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

Which statement about electrons and atomic orbitals is NOT true?

An electron has the same amount of energy in all orbitals

Which of the following is NOT part of John Dalton's atomic theory?

Atoms contain subatomic particles

Compare and contrast the beliefs of Democritus and the beliefs Bohr on the atom.

Democritus believed that atoms were uniform, solid, hard, incompressible, and indestructible, but Bohr believed that the electrons orbit at a fixed distance from the nucleus.

Which statement accurately represents the arrangement of electrons in Bohr's atomic model?

Electrons travel around the nucleus in fixed energy levels with energies that vary from level to level.

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

Ernest Rutherford

How was Bohr's atomic model similar to Rutherford's model?

It described a nucleus surrounded by a large volume of space.

Which statement about subatomic particles is NOT true?

Protons and neutrons have the same charge

Suppose an atom has a mass number of 23. Which statement is true beyond any doubt?

The number of protons in the nucleus does not equal the number of neutrons.

Rutherford's gold foil experiment provided evidence for which of the following statements?

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

Which statement is true about oxygen-17 and oxygen-18?

They are isotopes of oxygen.

Explain in detail the Thomson model of the atom and why it was important to the understanding of the atom as we know it today.

Thomson proposed the plum pudding model of the atom, which had negatively-charged electrons embedded within a positively-charged "soup."

Which of the following provides the best analogy for an electron in an atomic orbital?

a bee trying to escape from a closed jar

Which of the following most accurately represents John Dalton's model of the atom?

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

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

In an atomic model that includes a nucleus, positive charge is

concentrated in the center of an atom.

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

contains negatively charged particles.

The part of the atom that is negative is

electron

Which subatomic particle has a negative charge?

electron

The current model of the atom is called

electron cloud

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

like planets orbiting the sun

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

mass number- atomic number

The glowing of a neon light is caused by electrons emitting energy as they

move from higher to lower energy levels

The part of the atom that is neutral is

neutron

The diagram in Figure 4-1 shows the results of Rutherford's gold foil experiment. What caused some of the alpha particles to bounce straight back from the gold foil?

nuclei in the gold atoms

The part of the atom that is positive is

proton

What was the significance of Rutherford's experiment and what did it lead to?

showed that the atom is mostly empty space with a tiny, dense, positively charged nucleus. It led to scientist know that every atom has a nucleus

Democritus thought that matter was made of tiny particles

that could not be divided

Which of the following is unique for any given element?

the number of protons

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

the ratio of their masses is always the same.