Lecture_Feb_10_12

What are the general guidelines for writing Lewis formulas of molecules?

1. Determine total valence electrons; 2. Draw skeleton structure; 3. Arrange bonds & non-bonding electrons obeying Octet rule and Formal Charge.

In Lewis structures, which elements are typically central?

Less electronegative elements like carbon (C), nitrogen (N), and phosphorus (P) are typically central.

What is the total number of valence electrons in CO2?

16 valence electrons (C=4, O=12).

What shape does the H2O molecule have, and what is its bond angle?

Bent shape with a bond angle of 105°.

What is the geometry of a methane (CH4) molecule?

Tetrahedral geometry with bond angles of 109.5°.

What type of bond is between H and O in H2O?

Polar covalent bond (with an electronegativity difference of 1.4).

Is carbon tetrachloride (CCl4) a polar or non-polar molecule?

CCl4 is a non-polar molecule due to symmetrical tetrahedral geometry.

In IUPAC naming, how are ionic compounds named?

By stating the positive ion first followed by the negative ion.

How do covalent compounds generally indicate the lower electronegativity element?

The element with the lower electronegativity precedes that with the higher electronegativity.

What suffix is used when naming the second element in a binary compound where it is a non-metal?

The suffix '-ide' replaces the ending of the second element's name.

What does the oxidation number represent?

A positive or negative number that expresses the combining capacity of an element in a compound.

What oxidation number do elements in Group IA typically have?

+1 oxidation number.

What is the formula for sodium oxide?

Na2O, consisting of Na+ and O2-.

What is the total number of valence electrons in C2H3Br?

18 valence electrons (C=8, H=3, Br=7).

What is the overall charge of sodium bromide (NaBr) in terms of oxidation states?

Sodium (Na+) and bromide (Br-) maintain a neutral charge overall.

What is electron configuration?

Electron configuration is the distribution of electrons in an atom's orbitals, typically described using the Aufbau principle, Hund's rule, and the Pauli exclusion principle.

What is the electron configuration for potassium (K)?

The electron configuration for potassium (K) is 1s² 2s² 2p⁶ 3s¹.