LG 1.3-2.3 Review :)

Significant Figures

100

How many sig figs in 0.0010300g?

5 sf

200

Solve: 131.30+0.039 to correct sf

131.34

300

Solve: 150.56/0.0035 to correct sf

4.3 x 10^4

400

State the sig fig rule for addition/subtraction vs. multiplication/division.

Addition/Subtraction rounds to the least number of decimal places; Multiplication/Division rounds to the least number of total significant figures.

500

Express 0.00004050m in correct scientific notation with proper sig figs.

4.050 x 10^-5 m

Unit Conversions

100

Convert 150cm to m

1.5m

200

Convert 2.5kg to g

2.5 x 10^3 g

300

Convert 45.2 miles/hour to m/s (1mi=1.609km)

20.2 m/s

400

Calculate the density of a 1.25cm cube weighing 13.435 g.

6.89 x 10^3 kg/m^3

500

Convert 13.6 g/cm^3 to kg/m^3

1.36 x 10^4 kg/m^3

Periodic Table

100

Identify the group name for Br and I.

Halogens

200

Which element is a metalloid: B, C, S, In, or Pb?

Boron

300

Identify the alkali earth metal with the highest atomic number.

Radium

400

Classify NH3, pure gold, and a chocolate almond.

NH3 = Compound; Pure Gold = Element; Chocolate Almond = Heterogeneous Mixture.

500

Identify the least metallic element: C, Si, Ge, Sn.

C (Carbon) (Metallic character increases going down a group).

Atomic Structure

100

How many protons, neutrons, and electrons are in 35Cl-?

17 protons, 18 neutrons, 18 electrons.

200

 How does a neutral atom become a -2 ion?

 By acquiring two additional electrons.

300

Compare Atom A (23p, 31n, 18e) and Atom B (23p, 31n, 16e). How are they related?

They are ions of the same element (Vanadium)

400

Which of Ca, K, Al, Br, or Si is most likely to form a +1 ion?

Potassium (Alkali Metal)

500

Differentiate mass number vs. atomic mass vs. atomic number.

• Atomic Number: Number of protons.

• Mass Number: Protons + Neutrons (integer for a specific isotope).

• Atomic Mass: Weighted average mass of all naturally occurring isotopes.

Atomic Mass and Isotopes

100

What isotope of Sulfur (32S or 34S) is most abundant if its atomic weight is 32.06amu?

32S

200

Explain why average atomic mass on the periodic table is rarely a whole number.

Because it is a weighted average of all naturally occurring isotopes based on their percent abundance, rather than a single isotope's mass.

300

Calculate the average atomic mass of X if 75.0% is 35.0 amu and 25.0% is 37.0 amu.

35.5 amu

400

Element Y has two isotopes 10Y at 10.0 amu and 11Y at 11.0 amu. If average mass is 10.81 amu, which is more abundant?

11Y

500

35Cl (34.969 amu) and 37Cl (36.966 amu) have an average mass of 35.453 amu. Calculate % abundance.

35Cl: 75.76%, 37Cl: 24.24%