Texas Chemistry

Chem Unit 1 Review

Dr. Armstrong

(Georgia Standards of Excellence)

Multiple Choice

Standard SC1.c

Which of the following represents ALPHA decay?

Multiple Choice

Standard SC2.f

CH₄ has _____

• Four single bonds

• two triple bonds

• three triple bonds

CH4

• Carbon has 4 valence e^–

• Each hydrogen has 1 valence e^–

• 4 e^– + (4 x 1 e^–) = 8 e^–

• Put the H around the C and connect each with a single bond.

• 4 bonds x 2 e^– per bond = 8 e^– used

• None left over to make double or triple bonds

Multiple Choice

Standard SC2.f

For the bonds below, which is the strongest?

H–C

C=O

N≡N

• H–C

• C=O

• N≡N

Multiple Choice

Standard SC2.e

A compound is made of copper and phosphide ions in a ratio of 3:2. The IUPAC name for this chemical is

• copper phosphide

• copper(I) phosphide

• copper(II) phosphide

• copper(II) diphosphide

Copper and phosphide (P^3–, NOT phosphate, PO₄^3–) ions in a ratio of 3:2

• Cu₃P₂

• Copper is a transition metal, so it can have different oxidation numbers (charges)

• Phosphide is always –3. Since there are two, the negative charge is –6.

• The positive and negative have to balance --> +6

• +6 / 3 copper ions = each copper is +2

• Copper(II) iodide (Roman numeral II because charge +2)

Multiple Choice

Standard SC2.e

A chemical is analyzed and found to contain atoms in these ratios:

Element & Number of atoms

Carbon 1

Mercury 2

Oxygen 3

What is its formula?

• CHg₂O₃

• Hg₂CO₃

• CO₃Hg₂

Multiple Choice

Standard SC2.e

A compound is formed by the Calcium ion Ca²⁺ and the hydrogen carbonate ion HCO₃^–. What is the formula?

• Ca₂HCO₃

• Ca(HCO₃)₂

• CaH₂C₂O₆

Multiple Choice

Standard SC2.d

Which of the following is molecular?

**Molecular = all bonds are covalent, so it forms individual molecules, not an ionic crystal.**

• CO₂

• CaCl₂

• Fe₃(PO₄)₂

Multiple Choice

Standard SC2.d

Which of the following represents a nonpolar covalent molecule?

Multiple Choice

Standard SC1.g

A magnesium ion has the same electron configuration of which atom?

• Helium

• Fluorine

• Neon

• Krypton

Multiple Choice

Standard SC1.g

What is the electron configuration of a Ca²⁺ ion?

• 1s²2s²2p⁶3s²3p⁶

• 1s²2s²2p⁶3s²3p⁶4s²

• 1s²2s²2p⁶3s²3p⁶4s²4p²

Multiple Choice

Standard SC1.g

If this is the configuration of an atom's valence electrons, which atom could this be?

• barium (Ba)

• Iron (Fe)

• Iodine (I)

• Neon (Ne)

Multiple Choice

Standard SC1.f

Which of the following is the correct Lewis Dot structure for NaCl?

Multiple Choice

Standard SC1.f

As you go down the periodic table the size increases because

• there is greater nuclear charge ("proton pull")

• there are more shells of electrons

Multiple Choice

Standard SC1.f

Arrange the following by DECREASING radius (larger on the left, smaller on the right)

• Fl^– > Ne > Na⁺

• Ne > Na⁺ > Fl^–

• Na⁺ > Ne > Fl^–

Multiple Choice

Standard SC1.e

Based on the emission spectrum, the unknown sample on the bottom contains a mixture of gases

• A and B

• B and C

• A and D

• C and D

Multiple Choice

Standard SC1.e

This picture shows "excited" electrons moving from outer shells to inner shells (higher energy levels to lower energy levels). When this happens,

• energy is absorbed

• light (energy) of certain colors is emitted and causes the line spectrum "fingerprint"

Multiple Choice

Standard SC1.d

A sample of 100 grams of an element contained 86.2 grams (86.2% abundance) of an isotope with mass 34.02 amu, 11.3 grams (11.3% abundance) of an isotope with mass 35.62 amu, and 2.5 grams (2.5% abundance) of an isotope with mass 36.06 amu. To find the average atomic mass, which setup would be used?

• $$\left(0.862\right)\left(34.02\right)+\left(0.113\right)\left(35.62\right)+\left(0.025\right)\left(36.06\right)$$

• $$\frac{\left(34.02\right)\left(35.62\right)\left(36.06\right)}{\left(86.2\right)\left(11.3\right)\left(2.5\right)}$$

Multiple Choice

Standard SC1.d

The most common isotope of sulfur has 16 p⁺, 16 ¹₀n, and 16 e^–. Which of the following would be an isotope of sulfur?

• 17 p⁺, 16 ¹₀n, and 16 e^–

• 16 p⁺, 17 ¹₀n, and 16 e^–

• 16 p⁺, 16 ¹₀n, and 17 e^–

Multiple Choice

Standard SC1.b

The number of protons determines which element an atom is.

• True

• False

Multiple Choice

Standard SC1.b

Alkali metals and Halogens are very reactive because they just need to lose/gain 1 e^– to get an octet.

Alkaline earth metals are less reactive because they need to lose 2 e^– to get an octet.

Noble gases are not reactive because they already have an octet.

• True

• False

Groups

• Alkali Metals = 1 valence e^–

• Alkaline Earth Metals = 2 valence e^–

• Halogens = 7 valence e^–

• Noble Gases = 8 valence e^–

Multiple Choice

Standard SC1.a

Which of the following is the most accurate model of how electrons actually move around the nucleus?