Intro to Chemistry and Bonding: Carbon, Atoms, and Bonding Concepts

Flashcards cover core concepts from the lecture notes: matter, atoms, quantum numbers, electron configuration, Pauli principle, ionic and covalent bonding, bond energies, and basic organic chemistry ideas relevant to carbon.

Why is carbon central to organic chemistry?

Because carbon forms up to four covalent bonds (tetravalence), enabling diverse and complex molecular structures.

What is matter?

Anything that occupies space and has mass.

How is an element defined in chemistry?

By its atomic number—the number of protons in the nucleus.

What distinguishes isotopes of an element?

They have the same atomic number (same number of protons) but different atomic masses due to varying numbers of neutrons.

What describes the spatial arrangement of electrons in an atom?

Atomic orbitals, which are defined by wave functions.

Which part of the atom defines the element and which defines chemical properties?

The nucleus defines the element; the electron cloud defines chemical properties.

What are the three quantum numbers used to describe an electron's state?

Principal quantum number n, azimuthal quantum number l, and magnetic quantum number ml.

What does the principal quantum number n represent?

The energy level of the orbital; n = 1, 2, 3, …

What does the azimuthal quantum number l represent?

The orbital's angular momentum; l = 0, 1, 2, …, up to n−1.

What does the magnetic quantum number ml represent?

The orbital's orientation with respect to Cartesian axes; ml = −l,…,+l.

In an s orbital, what are the values of l and ml?

l = 0 and ml = 0; s orbitals have no directional preference.

What does the Pauli exclusion principle state?

No more than two electrons can occupy a given orbital; electrons in the same orbital must have unique quantum numbers.

How many electrons can hydrogen and helium have in their ground state, and in which orbital?

A duet (2 electrons) in the 1s orbital.

How many electrons do second-row elements (Li–Ne) accommodate in their ground state, and which orbitals participate?

An octet (8 electrons) with the 1s, 2s, and 2p orbitals (1s² 2s² 2p⁶).

What does Hund's rule state?

Orbitals are filled in order of increasing energy; degenerate orbitals are half-filled first, then filled.

What is an ionic bond and what drives its formation?

An electrostatic bond formed by transfer of electrons, creating cations and anions; lattice energy makes the formation of ionic compounds exothermic.

What is lattice energy?

The electrostatic energy of attraction in the ionic lattice; it drives the exothermic formation of ionic compounds.

What is a covalent bond and what is bond dissociation enthalpy (BDE)?

A bond formed by sharing electrons; BDE is the energy required to homolytically cleave the bond (e.g., H2 BDE ≈ 104 kcal/mol).

What is the difference between homonuclear and heteronuclear bonds in terms of polarity?

Homonuclear bonds (same element) are typically nonpolar; heteronuclear bonds (different elements) can be polar, with partial charges on atoms.

Why is CCl4 nonpolar despite polar C–Cl bonds?

Because the molecule’s symmetry cancels the bond dipoles, resulting in a net dipole moment of zero.