Chemistry Test 1

All atoms are neutral, with the number of protons equaling the number of neutrons

All atoms are neutral, with the number of ________ equaling the number of ________.

All atoms of the same element have the same number of protons.

All atoms of the same element have the same number of ________.

As a consequence of the discovery of the nucleus by Rutherford, the region outside the nucleus is believed to be largely empty space in which the electrons are located.

As a consequence of the discovery of the nucleus by Rutherford, the region outside the nucleus is believed to be largely _______ space in which the _______ are located.

As a result of his experiments involving firing positively charged particles at metal foil, Rutherford concluded that most of the mass of an atom was in the nucleus.

As a result of his experiments involving firing positively charged particles at metal foil, Rutherford concluded that most of the mass of an atom was in the _________.

Carbon-12 is the nuclide that the relative scale is based on

Atomic mass is a relative scale based on which nuclide?

Dalton's atomic theory include ideas such as all matter is made up of atoms which are invisible and all atoms of the same element have an identical mass and properties.

Dalton's atomic theory included which ideas?

To calculate the number of neutrons in an atom you do mass# - proton#

How do you calculate the number of neutrons in an atom?

It will take 15 years for one half of the original amount of material to decay if the half-life is 15 years.

If the half-life of a radioactive material is 15 years, how many years will it take for one half of the original amount of material to decay?

0.375 grams

If the half-life of potassium-24 is 10 hours, how much remains from an 12.0g sample after 50 hours?

In an uncombined, neutral atom the number of protons must equal the number of electrons

In an uncombined, neutral atom _______ must equal _______

In the equation E = mc^3 represents speed of light

In the equation E = mc^2, c represents ________

Isotopes of the same element have different numbers of neutrons

Isotopes of the same element have different numbers of ____________

Isotopes of the same elements have different mass numbers. (same number of protons, different number of neutrons)

Isotopes of the same elements have different ______ numbers.

Mass number is equal to the number of protons plus the number of neutrons

Mass number is equal to the ____________.

One atomic mass unit is equal to 1/12 the mass of one carbon-12 atom

One atomic mass unit is equal to _____ the mass of one carbon-12 atom

Potassium has a relative atomic mass that is not a whole number because some of its atoms have more mass than others.

Potassium has a relative atomic mass that is not a whole number because some of its atoms have more ________ than others.

The Greek philosopher that theorized all things are comprised of tiny particles called atoms was __________

The Greek philosopher that theorized all things are comprised of tiny particles called atoms was Democritus

The atomic number of an element is determined by the number of protons

The atomic number of an element is the total number of which particles in the nucleus?

The word atom comes from the Greek word atomos meaning indivisible. "A" means "not" and "tomos" means "cut" therefore meaning uncuttable

The word atom comes from the Greek word atomos meaning _________.

True: Atoms are mostly empty space

True or False: Atoms are mostly empty space

False: Atoms of isotopes of an element have different numbers of protons

True or False: Atoms of isotopes of an element have different numbers of protons

True: Atoms of the same element can have different masses

True or False: Atoms of the same element can have different masses

False: Dalton stated that all atoms are always in motion.

True or False: Dalton stated that all atoms are always in motion.

True: The nucleus of an atom has a positive charge

True or False: The nucleus of an atom has a positive charge

His ideas include: 1. all elements are composed (made up) of atoms and that it is impossible to divide or destroy an atom. 2. All atoms of the same element are alike. (One atom of oxygen is like another atom of oxygen). 3. Atoms of different elements are different. (An atom of oxygen is different from an atom of hydrogen).

What are some facts about John Dalton?

Protons have a positive charge and a mass of 1 atomic mass unit and are found in the nucleus, electrons have a negative charge and have almost no mass and are found orbiting the nucleus in clouds, and neutrons have a neutral charge and a mass of 1 atomic mass unit and are found in the nucleus.

What charge and mass do protons, electrons, and neutrons, have and where are they located?

Nothing happens to the number of protons when the mass number increases

What happens to the number of protons of an isotope when the mass number increases?

The atomic mass of an element is equal to the proton number plus the neutron number

What is the atomic mass of an element equal to?

The mass is 42

What is the mass number of an atom that has 20 protons, 22 neutrons, and 20 electron?

The symbol for zinc is Zn and it has 30 protons and 30 electrons.

What symbol does zinc have and how many protons and electrons does it have?

Fission is the term that refers to the splitting of atoms

What term refers to the "splitting" of atoms?

A sheet of paper/clothing

What thickness of material is needed to stop an alpha particle?

Several inches of lead, concrete, or steel will stop gamma radiation

What thickness of what material will stop gamma radiation?

The law of definite proportions is the law illustrated by the fact that water is always in a ratio of 2 to 1 of hydrogen to oxygen

Which law is illustrated by the fact that water is always in a ratio of 2 to 1 of hydrogen

J.J. Thomson was the scientist credited with the discovery of the electron as a result of work with cathode rays

Which scientist was credited with the discovery of the electron as a result of work with cathode rays?

Electrons have the smallest mass with 1/2000 AMU

Which subatomic particle has the smallest mass?

Protons and neutrons have the same mass

Which subatomic particles have the same mass?

Democritus was the first person to suggest the idea of atoms in the fourth century

Who was the first person to suggest the idea of atoms in the fourth century?

Rutherford's gold-foil experiment demonstrated that most of the atom is empty space.

____________ gold-foil experiment demonstrated that most of the atom is empty space.

A reaction in which two light nuclei combine to form a heavier nucleus is termed fusion.

A reaction in which two nuclei combine to form a heavier nucleus is termed ________.

The most penetrating and highest energy form of radiation is gamma rays.

The most penetrating and highest energy form of radiation is ________.

The nucleus is composed of protons and neutrons.

The nucleus is composed of __________.

The nucleus of an atom is composed of protons and electrons

The nucleus of an atom is composed of ________.

This is the element manganese-75 (Mn) and it has 25 protons, 25 electrons, and 50 neutrons

The nucleus of an element with an atomic number of 25 and a mass number of 75. How many protons, electrons, and neutrons does this contain? Which element is this?

Nuclear decay/radiation or radioactive decay is the release of particles and rays that occurs when an unstable nucleus breaks down.

The release of particles and rays that occurs when an unstable nucleus breaks down is called ___________.

The release of particles and rays that occurs when an unstable nucleus broke down is called nuclear decay/radiation or radioactive decay

The release of particles and rays that occurs when an unstable nucleus broke down is called __________.

The smallest part of an element that still has properties of that element is a/an atom

The smallest part of an element that still has the properties of that element is a/an ______