Chapter 3: Chemical Bonds Review

Flashcards covering key concepts from Chapter 3 on Chemical Bonds, including covalent and ionic bonding, Lewis structures, molecular and compound definitions, electronegativity, naming conventions for both covalent and ionic compounds, and polyatomic ions.

What are Group 8A elements called, and why are they stable?

They are called Noble Gases, and they are stable because they have a full valence shell.

What is the octet rule?

Representative elements tend to form compounds such that each atom has 8 electrons in its outermost shell, filling its valence shell.

How are Lewis structures used to represent molecules?

Lewis structures illustrate the shared and unshared valence electrons between atoms in a molecule, showing how they achieve a stable electron configuration.

What is a chemical bond?

A chemical bond occurs when two atoms are attracted enough to each other to stay together.

What is a covalent bond?

A covalent bond occurs when electrons are shared between two atoms.

Differentiate between a bonding electron pair and a lone pair.

A bonding electron pair refers to shared electrons in a covalent bond, while lone pairs (or non-bonding pairs) are electrons not involved in the covalent bond.

What is the definition of a molecule?

A molecule is a group of two or more atoms (identical or different) held together by chemical bonds.

What is the definition of a compound?

A compound is a combination of two or more different elements chemically bonded together.

Is every compound a molecule?

Yes, all compounds are molecules. However, not all molecules are compounds (e.g., H2 or F2 are molecules but not compounds).

How many electrons does a hydrogen atom need to fill its valence shell?

Hydrogen atoms need only one electron to fill their valence shell, achieving the electron arrangement of Helium.

How many bonds does an oxygen atom typically form, given it has 6 valence electrons?

An oxygen atom typically forms two bonds to achieve a full octet.

What is the difference between a single, double, and triple bond in terms of shared electrons?

A single bond involves one shared pair (2 electrons), a double bond involves two shared pairs (4 electrons), and a triple bond involves three shared pairs (6 electrons).

In a Lewis structure, what does a line represent?

Each line represents a bonding pair of electrons (two electrons).

Can non-metals always obey the octet rule?

No, non-metals in the third period and higher can sometimes violate the octet rule by sharing in more than 8 electrons.

What characterizes a polar covalent bond?

A polar covalent bond occurs when electrons are shared unevenly between atoms of different elements, leading to partial positive and negative charges.

What defines a nonpolar covalent bond?

A nonpolar covalent bond forms when two identical atoms have equal attraction to electrons, resulting in them being shared equally without forming charges.

What is electronegativity?

Electronegativity measures the attraction of an element for electrons in a chemical bond.

How does electronegativity trend across the periodic table?

Electronegativity increases from left to right across a period and from bottom to top within a group on the periodic table.

What are the first two IUPAC rules for naming binary covalent compounds?

1. Write the name of the least electronegative atom first. 2. Write the name of the second element, replacing its suffix with '-ide'.

Which prefixes are used to denote one, two, and three atoms of an element in a covalent compound name?

Mono- (for the second element only), Di-, and Tri- respectively.

What are some common names for H2O and NH3?

H2O is Water, and NH3 is Ammonia.

How do atoms with fewer than 4 valence electrons typically satisfy the octet rule?

They typically satisfy the octet rule by losing electrons to form positively charged ions (cations).

How do chlorine atoms (Cl) typically satisfy the octet rule?

Chlorine atoms typically gain one electron into their third shell to form a negatively charged chloride ion (Cl-), achieving a complete octet.

What are cations and anions, and how are they named in ionic compounds?

Cations are positively charged ions formed when atoms lose electrons (named by the atom name). Anions are negatively charged ions formed when atoms gain electrons (named by replacing the suffix with '-ide').

What type of forces form ionic bonds?

Ionic bonds are formed by the electrostatic attraction of oppositely charged ions.

What is the rule of charge balance for an ionic compound?

The total amount of positive charge from the cations must equal the total amount of negative charge from the anions, resulting in a neutral compound.

How is the charge on ions of transition metals typically indicated in their names?

Roman numerals or suffixes ('-ous' for lower charge, '-ic' for higher charge) are added to the stem word to indicate the charge (e.g., Iron (II) or Ferrous for Fe2+).

What is the general naming convention for ionic compounds?

Metal (cation) name + Non-metal (anion) stem + '-ide'.

What are polyatomic ions?

Polyatomic ions are ions that are made up of more than one atom (e.g., OH-, SO42-).

How are compounds with polyatomic ions balanced and written?

They are balanced following the charge balance rule, treating the polyatomic ion as a single unit. Parentheses are used if there is more than one polyatomic ion in the formula.

How can one typically recognize an ionic compound?

Ionic compounds typically contain a metallic element and a non-metallic element (or a polyatomic ion like NH4+).

How can one typically recognize a molecular (covalent) compound?

Molecular (covalent) compounds typically contain only non-metallic elements.

Why is it important for health sciences to understand the charges on elements (cations and anions)?

Understanding the charges is essential for comprehending cellular flow, as well as extracellular, intracellular, and interstitial components and their movement in the body.