CHEMISTRY TEST: PRATICE TEST

Subatomic particles can usually pass undeflected through an atom because the volume of an atom is composed of

largely empty space

The modern model of the atom is based on the work of

many scientists over a long period of time

Which subatomic particles each have a mass of approximately 1 amu?

proton and neutron

The bright-line spectrum of sodium is produced when energy is

released as electrons move from higher to lower electron shells

What is the electron configuration of a sulfur atom in the ground state?

2-8-6

Which electron configuration represents a potassium atom in an excited state?

2-8-7-2

What is the total number of neutrons in an atom of K-42?

23

A 100.00-gram sample of naturally occurring boron contains 19.78 grams of boron-10 (atomic mass = 10.01 atomic mass units) and 80.22 grams of boron- 11 (atomic mass = 11.01 atomic mass units). Which numerical setup can be used to determine the atomic mass of naturally occurring boron?

(0.1978)(10.01) + (0.8022)(11.01)

The nucleus of an atom of cobalt-58 contains

27 protons and 31 neutrons

What is the approximate mass of an atom that contains 26 protons, 26 electrons and 19 neutrons?

45 amu

The nucleus of an atom consists of 8 protons and 6 neutrons. The total number of electrons present in a neutral atom of this element is

8

Which statement matches a subatomic particle with its charge?

A neutron has no charge.

Which conclusion was a direct result of the gold foil experiment?

An atom is mostly empty space with a dense, positively charged nucleus.

Which one of the following is not one of the postulates of Dalton's atomic theory?

Atoms are composed of protons, neutrons, and electrons.

Which statement explains why a xenon atom is electrically neutral?

The atom has the same number of protons and electrons.

Which statement best describes electrons?

They are negative subatomic particles and are found surrounding the nucleus.

The weighted average of the atomic masses of the naturally occurring isotopes of an element is the

atomic mass of the element

All atoms of an element have the same

atomic number

Which phrase describes an atom?

a negatively charged electron cloud surrounding a negatively charged nucleus

In the wave-mechanical model of the atom, an orbital is defined as

a region of the most probable electron location

In the late 1800s, experiments using cathode ray tubes led to the discovery of the

electron

The part of an atom that has an overall positive charge is called

the nucleus

If two atoms are isotopes of the same element, the atoms must have

the same number of protons and a different number of neutrons