Chem Exam 3 Study

The tendency of atoms to prefer to have eight electrons in the valence shell

The ___________ in a formula give▪ the relationship of atoms in the formula▪ the moles of each element in 1 mole of a compound

An ________-_________

▪ provides us with energy from food

▪ provides electrical energy in batteries

▪ occurs when iron rusts

Carbon-containing compounds burn in oxygen gas to produce carbon dioxide (CO2), water (H2O), and energy

Practice: Identify the main type of attractive forces for each:1) ionic 2) dipole–dipole 3) hydrogen bonds 4) dispersion

• Yes

• Yes

In covalent compounds, polar molecules

▪ exert attractive forces called ______-_______ attractions

▪ form dipole attractions called hydrogen bonds between hydrogen atoms bonded to F, O, or N, and other atoms that are very electronegative

(same word)

•There are many ways compounds can interact

•The interactions are determined in large part by structure and polarity

•One compound may have several types of interactions

•The physical properties are largely determined by the interactions

▪ contains polar bonds

▪ has a separation of positive and negative charge called a dipole, indicated with + and –

▪ has dipoles that do not cancel

▪ A molecule with lone pairs on the central atom is almost always polar

Polarity arrows create a separation of charges called:

A _______ ________ bond

▪ occurs between nonmetal atoms

▪ has an unequal sharing of electrons

▪ has a moderate electronegativity difference