Question

Fill in the blank with the appropriate numbers for both electrons and bonds (considering that single bonds are counted as one, double bonds as two, and triple bonds as three). (a) Fluorine has valence electrons and makes bond(s) in compounds. (b) Oxygen has valence electrons and makes bond(s) in compounds. (c) Nitrogen has valence electrons and makes bond(s) in compounds. (d) Carbon has valence electrons and makes bond \((s)\) in compounds.

Short answer

(a) Fluorine has 7 valence electrons and makes 1 bond in compounds. (b) Oxygen has 6 valence electrons and makes 2 bonds in compounds. (c) Nitrogen has 5 valence electrons and makes 3 bonds in compounds. (d) Carbon has 4 valence electrons and makes 4 bonds in compounds.

Step-by-step solution

(a) Fluorine

: Fluorine is in group 17 of the periodic table and has 7 valence electrons. It needs 1 additional electron to fulfil the octet rule completely. Therefore, it forms one single bond in compounds. (a) Fluorine has 7 valence electrons and makes 1 bond in compounds.

(b) Oxygen

: Oxygen is in group 16 of the periodic table and has 6 valence electrons. It needs 2 additional electrons to fulfil the octet rule completely. Therefore, it forms two single bonds or one double bond in compounds. (b) Oxygen has 6 valence electrons and makes 2 bonds in compounds.

(c) Nitrogen

: Nitrogen is in group 15 of the periodic table and has 5 valence electrons. It needs 3 additional electrons to fulfil the octet rule completely. Therefore, it forms three single bonds, one single bond and one double bond, or one triple bond in compounds. (c) Nitrogen has 5 valence electrons and makes 3 bonds in compounds.

(d) Carbon

: Carbon is in group 14 of the periodic table and has 4 valence electrons. It needs 4 additional electrons to fulfil the octet rule completely. Therefore, it forms four single bonds, two single bonds and one double bond, or two double bonds in compounds. (d) Carbon has 4 valence electrons and makes 4 bonds in compounds.

Key concepts

Octet Rule

The Octet Rule is a fundamental principle in chemistry that helps us understand how atoms form chemical bonds. According to this rule, atoms tend to form bonds in a way that they end up with eight valence electrons. Having a full outer shell of electrons makes them more stable and less reactive. The Octet Rule mainly applies to main-group elements, especially those in the second row of the periodic table, such as carbon, nitrogen, oxygen, and fluorine. Atoms can achieve a full octet through several types of bonds:

• By gaining electrons, like non-metals do, to become more like noble gases.
• By losing electrons, like metals do, to attain a noble gas structure.
• By sharing electrons with other atoms, forming covalent bonds.

Understanding the Octet Rule is vital when predicting the types and number of bonds an atom can form in a molecule. For instance, carbon with four valence electrons forms four bonds to achieve an octet.

Chemical Bonds

Chemical bonds are the forces holding atoms together in molecules. These bonds form when atoms share or transfer valence electrons in order to achieve stability, often through the Octet Rule. There are several primary types of chemical bonds:

• Covalent Bonds: These occur when two atoms share one or more pairs of valence electrons. Types include single, double, and triple bonds. For example: Oxygen forms a double bond in O₂ molecules.
• Ionic Bonds: Formed when one atom transfers electrons to another, typically between metals and non-metals, resulting in attracted charged ions.
• Metallic Bonds: These are formed between metal atoms when they share a "sea" of electrons that provides structural cohesion.

Each bond type has distinct properties and plays a different role in the structure of compounds. Understanding how atoms bond is crucial for predicting molecular shapes, reactivity, and properties.

Periodic Table Groups

The Periodic Table is structured into groups that help predict the behavior of elements, including their valence electron count and bonding patterns. Groups, or families, are vertical columns in the table and are numbered from 1 to 18. Elements in the same group have similar chemical properties because they have the same number of valence electrons. This repetitive pattern, known as periodicity, is fundamental for understanding chemical reactions:

• Group 1 (Alkali Metals): These have 1 valence electron, making them highly reactive and eager to lose this electron to achieve an octet.
• Group 17 (Halogens): With 7 valence electrons, these elements need just one more electron to complete their octet and often form single covalent bonds.
• Group 18 (Noble Gases): Known for having a full set of valence electrons, making them generally unreactive, a term often called "inert."

Understanding the periodic table groups aids in predicting how different elements will interact in experiments and helps in forming chemical compounds.