Chemistry Chapters 3&4

The amount of a substance that contains a number of particles equal to the number of atoms in exactly 12 g of carbon-12 is referred to as a(n)

Mole

If two or more compounds are composed of elements A and B, the ratio of the masses of B combined with 1 g of A is always a ratio of small whole numbers. This is a statement of the law of

Multiple proportions

The short-range attractive forces that hold the nuclear particles together are called

Nuclear forces

Explain why the atomic mass of a particular isotope of an element differs from the average atomic mass of that element

The atomic mass of a single isotope of an element is its relative mass compared to the mass of carbon-12. The average atomic mass of an element is the weighted average of the masses of all naturally occurring isotopes of an element.

What is molar mass? How is it related to atomic mass?

The molar mass of a substance is the mass of one mole of the substance. A mole of any substance contains 6.022137x10^23 particles, or Avogadro's number of particles. The atomic mass is the mass of one atom.

Dalton's atomic theory helped to explain the law of conservation of mass because it stated that atoms

cannot be created or destroyed

If a particular compound is composed of elements A and B, the ratio of the mass of B to the mass of A will always be the same. This is a statement of the law of

definite proportions

The behavior of cathode rays in a glass tube containing gas at low pressure led scientists to conclude that the rays are composed of

negative particles

Millikan's experiments led to the determination

of the approximate value of the electron's mass

The discovery of the nucleus was a result of Rutherford's observation that a small percentage of the positively charged particles bombarding the metal's surface

were deflected back toward the source

What is an electrons mass number, relative charge, and location

0; 1 ; outside the nucleus (in the electron cloud)

A neutral atom of silicon-30 contains 14 protons. How many electrons does it have?

14

What is a neutrons mass number, relative charge, and location

1; 0; in the nucleus

What is a protons mass number, relative charge, and location

1; 1+; in the nucleus

The atomic number of nickel-60 is 28. How many neutrons does this isotope have?

32

Carbon-14 has 8 neutrons. What is the atomic number of carbon-14?

6

Dalton's theory agreed with the modern atomic theory in almost all cases. List the two statements that were later found to be in error

All atoms of the same element have the same mass; atoms cannot be subdivided

Concepts of Daltons atomic theory

All matter is composed of extremely small particles called atoms. All atoms of an element are identical in size, mass, and other properties; atoms of different elements differ in size, mass and other properties. Atoms cannot be subdivided, created, or destroyed. Atoms of different elements combine in simple whole-number ratios to form chemical compounds. In chemical reactions, atoms are combined, separated, or rearranged.

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

Atom

The number of protons in the nucleus of an element is called its ___ number

Atomic

The law of multiple proportions is demonstrated by the compounds

CO and CO2

The basic principles of atomic theory were first conceived by

Dalton

Because any metal cathode used in a cathode-ray tube produces the same charged particles, it was concluded that all atoms contain

Electrons

Most of the volume of an atom is occupied by the

Electrons

Atoms of one element that have different masses are called

Isotopes

The total number of protons and neutrons in the nucleus of an isotope is called its ___ number

Mass

Neutral atoms of the same element can differ in

Mass number