Chapter 4A

Question 0

we use the term ___ for the smallest particle capable of chemical interactions.

Answer 0

atom

Question 1

Who was the first to state that matter is made of separate, discrete particles.

Answer 1

The Greek philosopher Democritus

Question 2

This discovery led to the ___ of ____ _______This law states that every compound is formed of elements combined in specific ratios by mass that are unique for that compound.

Answer 2

Law of definite composition

Question 3

___ ____ first framed an atomic model based on experimental evidence instead of philosophy.

Answer 3

John Dalton

Question 4

The invention of the electrical battery by ______ ____ allowed scientists to study how matter behaves in the presence of an electrical current.

Answer 4

Alessandro Volta

Question 5

The English physicist ______ finally explained cathode rays and discovered the electrons

Answer 5

J. J. Thomson

Question 6

Another scientist, _______ , named these particles electrons (e–) in 1894.

Answer 6

George Johnstone Stoney

Question 7

______’s discovery of x-rays in 1896 triggered further experiments that led to the discovery of nuclear radiation.

Answer 7

Wilhelm Roentgen

Question 8

_____’s experiments with a form of radiation known as ______ led to new insights about the inner parts of the atom.

Answer 8

Ernest Rutherford

alpha particles

Question 9

In 1909 _____, one of Rutherford’s assistants, had one of his students design an experiment in which a beam of alpha particles was aimed at a sheet of thin gold foil.

Answer 9

Hans Geiger

Question 10

Rutherford reasoned that atoms must be mostly _______, otherwise most of the alpha particles should have been deflected.

Answer 10

empty space

Question 11

_____ reasoned that this region, the nucleus, as he called it, must be very small.

Answer 11

Rutherford

Question 12

_____ is the study of how matter produces and interacts with electromagnetic radiation.

Answer 12

Spectroscopy

Question 13

The simplest device for studying spectra, called the prism spectroscope, was invented in the 1850s by _____ and _____

Answer 13

Gustav Kirchhoff and Robert Bunsen

Question 14

A decade after discovering the nucleus, ____ identified the positive particles in the nucleus, which he called protons

Answer 14

Rutherford

Question 15

The number of protons in the nucleus is called an atom’s ___ ____

Answer 15

atomic number (Z).

Question 16

Who discovered the neutron

Answer 16

James Chadwick

Question 17

___ devise a model that describes the movement of the electrons around the nucleus

Answer 17

Niels Bohr

Question 18

When white light passes through a wedge of glass, known as a prism, it is dispersed to form a ____ ____ of all the colors of a rainbow.

Answer 18

continuous spectrum

Question 19

These spectra were called _____.

Answer 19

line spectra

Question 20

Bohr’s electron energy levels are called?

Answer 20

principal energy levels.

Question 21

Physicists describe these energy levels as ____, meaning that energy emissions come only in certain amounts or quantities.

Answer 21

quantized

Question 22

An atom’s lowest energy state, or its ___ ___, contains six or seven levels.

Answer 22

ground state

Question 23

Einstein’s theories of matter and energy suggested that light consisted of massless particles called ____.

Answer 23

photons

Question 24

____ suggested that if waves could behave like particles, then particles could behave like waves. This concept is known as _______

Answer 24

Louis de Broglie

de Broglie’s hypothesis

Question 25

_____ determined that it is impossible to know both the energy or momentum and the exact position of an electron at the same time. This concept, known as the _____ is a fundamental property of all submicroscopic systems.

Answer 25

Werner Heisenberg

Heisenberg uncertainty principle

Question 26

Bohr’s precise, planetlike orbits were replaced by ____ , or three-dimensional regions of probable position.

Answer 26

orbitals