HONORS CHEMISTRY STUDY GUIDE PAGE 1

NAME: CLASS PERIOD:

Disciplinary Core Ideas (NGSS) Each atom has a charged substructure consisting of a nucleus, which is made of protons and neutrons, surrounded by electrons. (HS-PS1-1) Student performance objectives At the end of this unit students should be able to:

1) Describe early milestones in the development of modern atomic theory. 2) State and apply the law of conservation of mass and the law of definite proportions. 3) State the premises of Dalton's atomic theory. 4) Describe J. J. Thomson's experimental evidence for the existence of electrons. 5) Describe Rutherford's scattering experiments and show how the results of the experiments imply the

existence of atomic nuclei. 6) List the three most important particles that all atoms are composed of, and describe their charges and

relative masses. 7) Understand the concept of atomic weight. 8) Describe how isotopic masses and isotopic abundances are measured experimentally using mass

spectrometry. 9) Describe the basic structure of the periodic table.

VOCABULARY DATE OUTLINE DATE

DUE

Alpha particle

Atom

Atomic mass

Atomic mass unit (amu)

Atomic number

Atomic theory

Beta particle

Cathode rays

Electrons

Gamma ray

Group

Isotopes

Law of constant composition

Mass number

Neutrons

Nuclear force

Nucleus

Period

Periodic table

Protons

Chapter 4: Atomic Structure 1) Early models of the atom

a) Dalton’s atomic theory

b) Size of the atom

2) Structure of the nuclear atom

a) Subatomic particles

b) The atomic nucleus

c) Rutherford’s experiment

3) Distinguishing among atoms

a) Atomic number

b) Mass number

c) Isotopes

i) Isotope notation

d) Atomic mass

4) Test/quiz

*Due on day of test

Horwat’s homepage with calendar: http://horwat.wicomico.wikispaces.net/Chemistry+%28Home%29

HONORS CHEMISTRY STUDY GUIDE PAGE 2

4.1: EARLY MODELS OF THE ATOM

Empedocles (490–430 BC): Greek philosopher

Leucippus' and Democritus' (460-370 BC): Greek philosopher

Plato and Aristotle (384-350 BC): Greek philosopher

Antoine Lavoisier (late 1700’s): French chemist (chemical revolution)

Joseph Proust (1799): French chemist (chemical revolution)

John Dalton (1803): English chemist, physicist and school teacher

Dalton’s atomic theory

1)

2)

3)

4)

5)

Size of the atom

HONORS CHEMISTRY STUDY GUIDE PAGE 3

The law of constant/fixed composition

Little Johnny D. wanted to verify the law of constant composition. He heated different masses of magnesium powder

in the presence of oxygen. Johnny then recorded the mass of each product in the table below.

Original mass (g)

of Mg

Total mass (g)

of MgO

Calculated mass of

oxygen (g)

% composition of

magnesium

% composition of

oxygen

2.00 3.34

2.40 3.98

2.80 4.64

3.20 5.30

When the magnesium reacted with the oxygen in the air, magnesium oxide (MgO) was formed. Use the following

formulas to calculate the percent composition of magnesium and oxygen.

1. What were little Johnny’s results? What is the % composition of MgO?

2. How does this experiment verify the law of constant composition?

3. If little Johnny was to get a hold of 100 kg of magnesium powder, how much MgO would he expect to get? Explain how you know this.

4. How could you apply this law to other compounds? How would you know if a substance is water (H2O)?

magnesiumproductofmass

magnesiumofmass%100 oxygen

productofmass

oxygenofmass%100

HONORS CHEMISTRY STUDY GUIDE PAGE 4

4.2: STRUCTURE OF THE NUCLEAR ATOM

HONORS CHEMISTRY STUDY GUIDE PAGE 5

4.3: DISTINGUISHING AMONG ATOMS: ISOTOPIC/NUCLEAR NOTATION FOR ATOMS AND IONS

Standard nuclear notation shows the chemical symbol, the mass

number and the atomic number of the isotope.

Example: the isotopes of carbon. The element is determined by

the atomic number (Z) 6. Carbon-12 is the common isotope, with

carbon-13 as another stable isotope which makes up about 1%.

Carbon 14 is radioactive and the basis for carbon dating.

Ionic charge comes from the difference between the number of

protons (Z number) and number of electrons.

11) Write the chemical symbol for the ion with 12 protons and 10 electrons.

19) How many protons (P+), neutrons (N), and

electrons (e-) are present in the ion?

12) Write the chemical symbol for the ion with 74 protons and 68 electrons.

20) How many protons (P+), neutrons (N), and

electrons (e-) are present in the ion?

13) Write the chemical symbol for the ion with 95 protons and 89 electrons.

21) How many protons (P+), neutrons (N), and

electrons (e-) are present in the ion?

14) Write the chemical symbol for the ion with 33 protons and 36 electrons.

22) Write the complete chemical symbol for the ion with 84 protons, 125 neutrons, and 80 electrons.

15) Write the chemical symbol for the ion with 29 protons and 27 electrons.

23) Write the complete chemical symbol for the ion with 27 protons, 32 neutrons, and 25 electrons

16) How many protons (P+), neutrons (N), and

electrons (e-) are present in the ion?

24) Write the complete chemical symbol for the ion with 73 protons, 108 neutrons, and 68 electrons

17) How many protons (P+), neutrons (N), and

electrons (e-) are present in the ion?

25) Write the complete chemical symbol for the ion with 31 protons, 39 neutrons, and 28 electrons

18) How many protons (P+), neutrons (N), and

electrons (e-) are present in the ion?

26) Write the complete chemical symbol for the ion with 6 protons, 6 neutrons, and 6 electrons

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4.3: ISOTOPES AND AVERAGE ATOMIC MASS

HONORS CHEMISTRY STUDY GUIDE PAGE 8

SUMMARY/REVIEW

4-1 Defining the atom, page 101

Elements are composed of tiny particles called ____________________. Atoms of any one element are

_______________________ from those of any other element. Atoms of different elements can form

_______________________ by combining in whole-number ratios. Chemical reactions occur when atoms are

_______________________.

4-2 Structure of the Nuclear Atom, page 104

Dalton theorized that atoms are indivisible, but the discovery of _______________________ particles

changed this theory. Scientists now know that atoms are made up of electrons, which have a

_______________________ charge; _______________________, which have a positive charge; and

_______________________, which are neutral. The latter two particles are found in the _______________________

of the atom. It was _______________________ who discovered the nucleus of the atom. The nucleus, which has a

_______________________ charge, occupies a very small volume of the atom. In contrast, the negatively charged

_______________________ occupy most of the volume of the atom.

4-3 Distinguishing among atoms, page 110

The number of _______________________in the nucleus of an atom is the atomic

_______________________ of that element. Because atoms are electrically neutral, the number of protons and

_______________________ in an atom are equal. The total number of _______________________ and neutrons in

an atom is the mass number. Atoms of the same element are identical in most respects, but they can differ in the

number of _______________________ in the nucleus. Atoms that have the same number of protons but different

mass numbers are called _______________________.

The _______________________ of an element is the weighted average of the masses of the isotopes of that

element. Each of the three known isotopes of hydrogen has _______________________ proton(s) in the nucleus.

The most common hydrogen isotope has _______________________ neutrons. It has a mass number of

_______________________ and is called hydrogen-1.