Chemistry Chapter 2 Quiz

Atomic Charge and Valence Electrons

• Strontium atom has a charge of +2 due to its position in group 2.
• Maximum charge an ion can typically have is +3.
• The number preceding the letter 'A' in representative elements indicates the number of valence electrons.
• Helium has 2 valence electrons, unlike Magnesium and Silicon, which follow their group number for valence count.

Electron Configuration and Bonding

• Gallium's electron configuration can be determined using the aufbau diagram.
• Halides are negative ions formed when halogen atoms gain an electron.
• The octet rule states that atoms aim for a stable configuration of 8 valence electrons.
• Ionic bonds are formed through the electrostatic attraction between oppositely charged ions.

Ionic Compounds and Conductivity

• Electron dot notation represents valence electrons as dots around the atomic symbol.
• The coordination number is the count of oppositely charged ions surrounding each ion in a crystal.
• Metallic bonds involve the attraction between free-floating valence electrons and positively charged metal ions.

Ionic Characteristics and Reactions

• Salts are neutral ionic compounds.
• Oxygen achieves the octet rule by accepting two electrons for a stable outer level.
• A pseudo noble gas configuration includes 18 electrons in the arrangement of 2 electrons in s, 6 in p, and 10 in d subshells.
• Silver loses 1 electron, and Barium loses 2 electrons to stabilize as ions.

Ion Formation and Types

• The ion formed when potassium achieves noble gas configuration is K+1.
• Both iodine and fluoride gain one electron to form I- and F- ions, respectively.
• Nitrogen gains 3 electrons to achieve a pseudo noble gas configuration.
• Group 1 elements, such as potassium and sodium, form +1 charged ions.

Physical Properties and Crystal Structures

• Ionic compounds generally exist as crystalline solids at room temperature.
• In sodium sulfide, the cation has a charge of +1.
• Ionic compounds are commonly referred to as salts, characterized by electrostatic bonding of positive and negative ions, with nonmetals frequently in the mix.
• Nitrogen transfers 3 electrons to potassium when potassium nitride is formed; typically, nonmetals gain and metals lose electrons during reactions.

Coordination and Metallic Bonds

• In hexagonal close-packed crystals, each atom is surrounded by 12 oppositely charged ions.
• Cesium chloride exhibits a coordination number of 8 in its metallic crystal structure.
• Three types of metallic crystal structures include hexagonal close-packed, face-centered cubic, and body-centered cubic.

Properties of Metals and Alloys

• Metallic bonds allow free-floating electrons to conduct electricity, making metals malleable and ductile.
• Potassium bromide can conduct electricity when melted or disassociated in water.
• Potassium chloride possesses a high melting point due to its ionic nature.
• Metals typically lose electrons, while nonmetals gain them.
• Alloys are preferable as they combine the properties of constituent elements rather than relying on a single element's characteristics.

Test your knowledge on basic chemistry concepts involving atomic charges and valence electrons. This quiz covers crucial information about elements like strontium, magnesium, helium, and silicon. Perfect for students wanting to reinforce their understanding of group elements and their properties.