Covalent Bonding Flashcards

Covalent Bonding Overview

• Covalent compounds are known as molecular compounds.
• A covalent bond occurs between two nonmetals.
• Nonmetals exhibit high electronegativity and electron affinity.
• Nonmetals aim to gain electrons to achieve stability.

Key Concepts in Covalent Bonding

• Electronegativity is the tendency of an atom to attract shared electrons.
• Electron affinity refers to an atom's ability to attract and hold additional electrons.
• Covalent bonding can be likened to two equally strong individuals engaging in a tug-of-war, where neither side can overpower the other.

Molecular Structure

• A covalent bond forms a molecule, defined as a neutral group of atoms connected by covalent bonds.
• Energy is released whenever a chemical bond forms.
• In Lewis dot notation, a dash between two elements signifies a single covalent bond.

Bond Energy and Length

• Breaking a bond requires energy.
• Bond dissociation energy is the energy needed to sever a bond between two covalently bonded atoms.
• Bond length is the average distance between the nuclei of bonded atoms.
• Short bond lengths indicate atoms are very close, necessitating more energy for separation.
• Larger atoms possess longer bond lengths due to additional energy levels, thus needing less energy for separation.

Diatomic Molecules and Valence Electrons

• The seven diatomic molecules include H2, N2, O2, F2, Cl2, Br2, and I2.
• Metals typically have 1-3 valence electrons, while nonmetals have 5-7 valence electrons.

Stability through Electron Sharing

• Shared electrons in a covalent bond occupy the outer orbitals of both atoms, leading to stability.
• An exothermic reaction occurs when energy is released as atoms transition from a high to a low energy state during bond formation.
• Covalent bond formation results from the attraction between one atom’s electrons and another atom’s positive nucleus.

Attractive and Repulsive Forces

• If two atoms begin to separate, the attractive forces between one atom's electrons and the other's nucleus pull them back together.
• If atoms come too close, their positive nuclei repel each other, causing separation.
• Atoms oscillate but maintain an average distance apart.

Properties and States of Covalent Compounds

• Molecular compounds generally have low melting and boiling points.
• They are poor electrolytes and do not conduct electricity well.
• At room temperature, most molecular compounds are found as liquids or gases.

Naming Molecular Compounds

• To name molecular compounds, first list the first element in the compound, adding a prefix for multiple atoms.
• For the second element, always include a prefix and use the "ide" suffix.

Prefixes for Number of Atoms

• Mono = 1
• Di = 2
• Tri = 3
• Tetra = 4
• Penta = 5
• Hexa = 6
• Hepta = 7
• Octa = 8
• Nona = 9
• Deca = 10

Electronegativity and Bonding

• Electronegativity values help predict the bond type between two elements.
• In reactions between identical nonmetals, electrons are shared equally, forming a nonpolar covalent bond.