In the NFPA safety diamond, what does the yellow color stand for?

Unstability/Reactivity Red? Flammability Blue? Health

What is the rule for multiplication/division using significant figures?

Round your answer to the least number of sig figs.

What is the rule for addition/subtraction using significant figures?

Round your answer to the least number of decimal places.

Round the following number to 2 significant figures:

3071.012 Answer: 3100 Round the same number to 2 decimal

places. 3071.01

What does MSDS stand for? How do we use them?

Material Safety Data Sheet

What type of mixture is shown below?

Homogeneous Mixture Alloy

Define the term heterogeneous mixture and give 2 examples.

What happens to an atom when we have 2 more protons than electrons.

It IONIZES and becomes a cation with an oxidation number of +2

Define Ion:

What scientist used cathode ray tubes in his experiments?

JJ Thomson

What subatomic particle did he identify?

Electrons

Round the following number to 3 decimal places:

5412.02580 Answer: 5412.026 Round the same number to 3 sig.

figs. 5410

What is an isotope?

Same element different mass because of a differing number of neutrons.

Who can tell me the difference between average atomic mass and mass number?

Who conducted the gold foil experiment? Ernest Rutherford

What did he conclude from his findings?

Ernest Rutherford concluded that atoms were mostly empty space with very a very dense positively charged nucleus.

Who proposed that electrons traveled in fixed paths around the nucleus?

Neils Bohr What was he trying to explain?

Round the following number to 3 Significant figures.

0.0095661 Answer: 0.00957 Round the same number to 2

decimal places

Why do scientist have to use significant figures?

Calculations cannot be more accurate than their measurements.

What subatomic particle has the same mass as a proton.

Neutron What’s the difference between them? Neutrons have no charge

Round the following number to 2 decimal places.

109.0053 Answer: 109.01 Round the same number to 1 sig.

fig.

What are valence electrons?

Electrons on the outermost ring/shell.

What is meant by oxidation number?

The actual charge of an ion.

How do we know what is the oxidation number of an atom?

By looking at the periodic table, # of valence electrons.

What is the Octet rule?

All atoms want to have a full outer energy level. (8 electrons)

Round to 4 significant figures:

4562.36951 4562 Round the same number to 4 decimal

places 4562.3695

What is the definition for density?

How tightly packed molecules are within a substance.

How many protons does Oxygen-16 have?

8 protons

How many electrons would a gold atom have if I tell you it has an oxidation number of +2.

77

How many protons does Fluorine-20 have?

9 protons

How many electrons would a magnesium atom have if I tell you it has an oxidation number of +2.

10

How many neutrons does Oxygen-18 have?

10 neutrons

How many electrons would a sulfur atom have if I tell you it has an oxidation number of -2.

18

How many neutrons does Fluorine-20 have?

11 neutrons

Draw the lewis dot diagram for magnesium

For calcium:

a form of notation which shows how the electrons are distributed among the various atomic orbital and energy levels. 

The format consists of a series of numbers, letters and superscripts as shown below:

1s2