Chemistry Test Bruce Unit 3

Refers to an atom by identifying its nuclear composition

nuclide

E = mc^2 M represents ...

mass

Alpha charge

+2

Each alpha particle carries an electric charge of _______________

+2

Beta charge

-1

Each beta particle carries an electric charge of _______________

-1

Each gamma ray carries an electric charge of _______________

0

Gamma charge

0

Gamma mass (amu)

0

Neutron relative charge

0

When a radioactive nucleus gives off a gamma ray, its atomic number increases by _______________

0 (zero)

Neutron relative mass

1

Proton relative mass

1

Proton relative charge

1+

Electron relative charge

1-

The neutron-to-proton ratio for the isotope sodium-23 is

1.1:1

One atomic mass unit is

1/12 the mass of a carbon-12 atom

Beta mass (amu)

1/1840

Electron relative mass

1/1840

Rutherfordium has an atomic number of 102. How many protons and electrons does it have?

102

A lightweight isotope is likely to be stable if the ratio of protons to neutrons in its nucleus is

1:1

Zinc has 30 protons. What is its atomic number?

30

Alpha mass (amu)

4

Oxygen has 8 electrons. How many protons does oxygen have?

8

Astatine has 85 protons. What is its atomic number?

85

Believed matter was composed of such things as earth, water, air, and fire

Aristotle

% 1 x M 1 + % 2 x M 2 + % 3 x M 3 + ... =

Average Atomic Mass Formula

Explain why the path of the beta particles bends more than the path of the alpha particles.

Beta particles have less mass than alpha particles, more greatly affected by electric field

First person to propose the idea that matter was not infinitely divisible, but made up of individual particles called atomos, from which the English word atom is derived

Democritus

The 3 types of radiation were first identified by _______________

Ernest Rutherford

Who proposed the nuclear atomic model?

Ernest Rutherford

Who determined the mass-to-charge ratio of an electron?

J.J. Thomson

Revived the idea of the atom in the early 1800s based on numerous chem reactions... atomic theory easily explained conservation of mass in a reaction as the result of the combination, separation, or rearrangement of atoms

John Dalton

Who calculated the mass of an electron?

Millikan

Explain why the gamma rays do not bend.

They're just energy... no charge

The discovery of the __________ in 1895 by Wilhelm Roentgen opened a whole new field of research.

X-ray

Wilhelm Roentgen discovered the form of energy known as _______________

X-rays

The other types of radiation consist of particles. The form of radiation containing the heavier particle is made up of helium nuclei called ____________________.

alpha particle

What units is the atomic mass reported in?

amu's

The smallest particle of an element that retains the properties of the element is called a(n)

atom

The ___________ of an element is the weighted average mass of the isotopes of that element.

atomic mass

The number of protons in the nucleus of an atom identifies the element and is known as the element's _______________

atomic number

Z represents the _____________

atomic number

The form of radiation containing the lighter particle consists of electrons called ________________.

beta particles

Fast-moving electrons

beta radiation

The atomic mass of an atom is usually not a whole number because it accounts for

both the relative abundance and the mass of each of the atom's isotopes

In nature, most elements are found as mixtures of isotopes. Usually, the relative abundance of each isotope is _____________

constant

The mass of an electron is: a) smaller than the mass of a proton b) smaller than the mass of neutron c) a tiny fraction of the mass of an atom d) all of the above

d) all of the above

The only nucleon among the following is: a) electron b) positron c) beta particle d) neutron

d) neutron

Electron symbol

e-

Beta composition

electrons

X represents the _____________

elemental symbol

E = mc^2 E represents ...

energy

Ancient philosophers regularly performed controlled experiments.

false

Dalton was correct in thinking that atoms could not be divided into smaller particles.

false

Dalton's atomic theory stated that matter is mostly empty space.

false

Democritus proposed that atoms are held together by chemical bonds, but no one believed him.

false

Most atoms have either a positive or a negative charge.

false

The number of neutrons in an atom is referred to as its atomic number.

false

The form of nuclear radiation that has the greatest penetrating power is the _______________

gamma ray

There are three common forms of radiation. One type is a form of energy known as ______________.

gamma ray

Alpha compisition

helium nuclei

Gamma composition

high-energy electromagnetic radiation

Carbon-14 is in _____________ notation

hyphen

Atoms with the same number of protons but different numbers of neutrons are called _______________

isotopes

The difference in mass between the true mass of an atom and the sum of its component particles

mass defect

A represents the _____________

mass number

The ______________ is the sum of the protons and neutrons in the nucleus.

mass number

The number of stable isotopes that exist compared to the number of unstable isotopes is

much less

Neutron symbol

n

During electron capture, a proton in the nucleus of an atom is converted into a(n)

neutron

Atoms located above the band of stability on a graph of numbers of neutrons versus number of protons are usually unstable because they contain too many

neutrons

The energy released when a nucleus is formed from its nucleons

nuclear binding energy

Particles or EM radiation emitted from the nucleus during radioactive decay

nuclear radiation

A reaction that involves a change in an atom's nucleus

nuclear reaction

A particle in the nucleus (protons and neutrons)

nucleon

Neutron location

nucleus

Proton location

nucleus

Atomic mass is equal to what?

number of protons and electrons

One amu is nearly, but not exactly, equal to ______ proton(s) and ________ neutron(s).

one, one

Proton symbol

p+

Which plate do the beta particles bend toward? Explain.

positive plate b/c both particles negatively charged

The positron produced during positron emission comes from a(n)

proton

What equals mass?

protons + neutrons

The Curies discovered that some forms of matter give off ___________, a combination of particles and energy.

radiation

The rays and particles emitted by a radioactive material

radiation

The process in which an unstable nucleus loses energy spontaneously

radioactive decay

The spontaneous disintegration of a nucleus into a slightly lighter nucleus, accompanied by the emission of particles, EM radiation, or both

radioactive decay

An unstable nucleus that undergoes radioactive decay

radioactive nuclide

Marie Curie named this process _____________. Another term used to describe the process by which one element spontaneously changes into another element is ______________.

radioactivity, radioactive decay

Any isotope that undergoes such changes is called a(n) ________.

radioisotope

Electron location

space surrounding nucleus

E = mc^2 C represents ...

speed of light

Both Democritus and Dalton suggested that matter is made up of atoms.

true

Dalton thought that all atoms of a specific element have the same mass.

true

Dalton's atomic theory stated that atoms of different elements combine in simple whole-number ratios to form compounds.

true

Dalton's atomic theory stated that atoms separate, combine, or rearrange in chemical reactions.

true

Dalton's atomic theory was based on careful measurements and extensive research.

true

Philosophers formulated explanations about the nature of matter based on their own experiences.

true

The number of protons in an atom identifies it as an atom of particular element.

true

The periodic table is arranged by increasing atomic number.

true

*Atomic number is equal to the number of electrons in an atom.

true* (only if neutral)