CEM 141 – Chapter 3: Elements, Bonding, and Physical Properties

A set of flashcards covering the key concepts and definitions from Chapter 3 on elements, bonding, and physical properties.

What evidence exists that atoms exist?

Various experimental observations and measurements, including interactions between particles.

What are emergent properties?

Properties that arise when atoms interact to form larger collections.

What is the stable distance between hydrogen atoms called?

The distance at which the potential energy is at a minimum, typically when the atoms form a covalent bond.

Why do covalent bonds form between atoms?

Atoms form bonds to share electrons and achieve a full octet, minimizing potential energy.

What is the difference in strength between hydrogen bonds and helium interactions?

Hydrogen forms strong covalent bonds while helium has weak London dispersion forces.

How does Molecular Orbital (MO) Theory describe the interaction of atomic orbitals?

Atomic orbitals combine to form bonding and antibonding molecular orbitals, affecting chemical stability.

Why do two hydrogen atoms form a bond?

Because they have two electrons in a bonding molecular orbital, leading to stabilization.

What happens when two helium atoms interact?

They do not form a bond due to the presence of two electrons in an antibonding molecular orbital.

What is the outcome when the number of molecular orbitals increases in metals?

It decreases the energy gap between them, allowing electrons to move freely.

How do phase changes like melting and boiling relate to energy?

They absorb or release energy as intermolecular attractions are overcome.

What is the main structural difference between diamond and graphite?

Diamond has a tetrahedral structure while graphite has a planar structure with layers.

What type of bonding explains the high melting point of carbon?

The strong covalent bonds formed by the tetrahedral geometry of carbon atoms.

How do sp3 hybridized orbitals contribute to the properties of diamond?

They create strong sigma bonds that give diamond its high hardness and melting point.

What hybridization occurs in graphite to form its bonding structure?

sp2 hybridization leading to a trigonal planar geometry with delocalized pi electrons.

What are the properties of graphite?

Good electrical conductor, shiny, and slippery due to layered structure.

What evidence exists that atoms exist?

Various experimental observations and measurements, including interactions between particles.

What are emergent properties?

Properties that arise when atoms interact to form larger collections.

What is the stable distance between hydrogen atoms called?

The distance at which the potential energy is at a minimum, typically when the atoms form a covalent bond.

Why do covalent bonds form between atoms?

Atoms form bonds to share electrons and achieve a full octet, minimizing potential energy.

What is the difference in strength between hydrogen bonds and helium interactions?

Hydrogen forms strong covalent bonds while helium has weak London dispersion forces.

How does Molecular Orbital (MO) Theory describe the interaction of atomic orbitals?

Atomic orbitals combine to form bonding and antibonding molecular orbitals, affecting chemical stability.

Why do two hydrogen atoms form a bond?

Because they have two electrons in a bonding molecular orbital, leading to stabilization.

What happens when two helium atoms interact?

They do not form a bond due to the presence of two electrons in an antibonding molecular orbital.

What is the outcome when the number of molecular orbitals increases in metals?

It decreases the energy gap between them, allowing electrons to move freely.

How do phase changes like melting and boiling relate to energy?

They absorb or release energy as intermolecular attractions are overcome.

What is the main structural difference between diamond and graphite?

Diamond has a tetrahedral structure while graphite has a planar structure with layers.

What type of bonding explains the high melting point of carbon?

The strong covalent bonds formed by the tetrahedral geometry of carbon atoms.

How do sp3 hybridized orbitals contribute to the properties of diamond?

They create strong sigma bonds that give diamond its high hardness and melting point.

What hybridization occurs in graphite to form its bonding structure?

sp2 hybridization leading to a trigonal planar geometry with delocalized pi electrons.

What are the properties of graphite?

Good electrical conductor, shiny, and slippery due to layered structure.

What are the fundamental components of an atom?

Protons, neutrons, and electrons.

What are Van der Waals forces?

Weak intermolecular forces that include dipole-dipole interactions, dipole-induced dipole interactions, and London dispersion forces.

What is represented by the minimum on a potential energy curve for two interacting atoms?

The most stable internuclear distance (bond length) where attractive and repulsive forces are balanced, resulting in the lowest potential energy.

What is a sigma bond?

A type of covalent bond formed by the direct, head-on overlap of atomic orbitals, resulting in electron density concentrated along the internuclear axis.

What is a pi bond?

A type of covalent bond formed by the sideway overlap of p orbitals, resulting in electron density above and below the internuclear axis.