Unit 3 Exam - Honors Chemistry

Atomic Radius

The distance between an atom's nucleus and other electron shell

Atomic Radius Trends

Molecular vs Ionic Compounds

Molecular - nometal + nonmetal (covalent bond) - prefixes Ionic - Metal + nonmetal (held together by electrostatic forces, cation + anion) - no prefixes

Electronegativity

measure of the ability of an atom's nucleus to attract electrons from a different atoms within a covalent bond

Electronegativity Trends

Ionization Energy

amount of energy needed to remove an electron from an atom

Ionization Energy Trends

Types of elements

metals nonmetals metalloids - elements with physical and chemical properties of both metals and non-metals

Valence electrons

Diatomic

consisting of two atoms

which elements are diatomic?

Hydrogen. Nitrogen. Oxygen. Fluorine. Chlorine. Bromine. Iodine

How do you know if a compound is polar or nonpolar?

Polar molecules are asymmetric, either containing lone pairs of electrons on a central atom or having atoms with different electronegativities bonded

Formula for each molecular compound a. sulfur dioxide b. carbon tetraflouride c. disphosphorous pentoxide

a. SO₂ b. CF₄ c. P₂O5

Molecular Compounds Prefixes and Suffixes

Prefixes 1- mono 2- di 3- tri 4- tetra 5- penta 6- hexa 7- hepta 8- octa, 9- nona 10- deca Suffix -ide

Why does a metal form a positive ion with bonding?

Metals tend to form positive (+ charged) ions because they have low numbers of valence electrons, which they can lose easily

Give the formula for each of the following ionic compounds a. calcium iodide b. copper(II) chloride c. ammonium sulfate

a. CaI₂ b. CuCl₂ b.(NH₄)₂SO₄

Families and Groups

Covalent bond

A covalent bond consists of the mutual sharing of one or more pairs of electrons between two atoms

What is the strongest and weakest type of covalent bond?

Strongest - triple bond Weakest - single bond

Formula for Carbon Tetrachloride

CCl4

Formula for Calcium chloride

CaCl2

Nomenclature for dinitrogen dioxide

N2O2

Which element is more elctronegative? K, Ca, As, Br, Kr

Br

Which has the largest radii? K, Ca, As, Br, Kr

K

Which element is the lowest electronegativity? K, Ca, As, Br, Kr

Kr ** noble gases do not have electronegativity

Lewis Dot Structure for CO2

- 16 valence electrons - steric number of 2 - linear shape - no lone pairs - nonpolar

Lewis Dot Structure for H20

- 8 valence electrons - steric number of 4 - bent shape - 2 lone pairs - polar

Lewis Dot Structure for NH3

- 8 valence electrons - steric number of 4 - pyramid shape - one lone pairs - polar

Polarity

polarity is a separation of electric charge leading to a molecule or its chemical groups having an electric dipole moment, with a negatively charged end and a positively charged end

Stallion Starter: a. How many e do haolgens exchange when obtaining a noble has config.? b. How many e do alkaline earth exchange when obtaining a noble gas config.? c. How many e do alkali exchange when ionizing?

a. +1 b. -2 c. +1

steric number

The number of atoms, groups, or lone pairs around a central atom

lone pairs

pair of valence electrons that are not shared with another atom in a covalent bond