Chapter 4:Ionic and Molecular Compounds

Most elements do what?

React and form compounds.

What are the exceptional elemental groups who do not react and form compounds?

Noble Metals (Gold, Silver and Platinum)& Noble Gases; Group VIIIA)

Why don’t noble gases react?

They have a filled outer energy level. Has an octet already.

In binary ionic compounds, what do metals do? 

Metals lose their electron to form a positive ion. 

In binary ionic compounds, what do nonmetals do? 

Nonmetals gain an electron which forms an anion. The name of the anion ends in -ide.

What forms binary ionic compounds?

Metals and Nonmetals.

To name a binary ionic compound; what must you do?

Name the metal and then the nonmetal with an -ide ending. With Transition and post transition metals you will include a roman numeral.

How do you write out the formula for binary ionic compound? 

Determine the charge on the cation and anion. Find the least common multiple and determine the subscripts. 

What is the distance between the two nuclei called?

Bond length.

The energy required to break the bond is called?

Bond energy.

What is the effective nuclear charge?

A measure of how effective the positive nucleus is at attracting valence electrons.

Ionization energy:

The energy required to remove a valence electron from an atom and a positive charged atom. (ion) It measures how tightly electrons are held by the atom, the higher the IE, the tighter the electrons are held. 

Why does IE increase across a period and decrease down a group?

It increases across a period because it required more energy to remove an electron as you go across the periodic table and easier to remove an electron as you go down a group. 

Explain the trend in IE across a period:

More electrons added to the same energy level. More protons, no additional shielding. The effective nuclear charge increases. electrons are held tighter. 

Explain the trend in IE down a group:

Electrons added to further energy levels. More protons but has more shielding. Nuclear charge decreases and electrons are held less tightly which makes it easier to remove. 

Electronegativity: 

Attract electrons to itself when it bonds with another atom. The greater the electronegativity an atom, the greater its attraction for electrons. 

What is the trend for electronegativity?

Electronegativity values increase across a period and up a group. HELIUM IS NOT on electronegative scale. 

electronegativity is high for what elements and low for what elements?

high for nonmetals (right side of periodic table) and low for metals (left side of periodic table) 

When forming bonds with other atoms, what do metals need to do?

Lose electrons to get an octet. electrons are easy to get rid of.

low ionization energy and low electronegativity values. 

When forming bonds with other atoms, what do nonmetals need to do?

Gain electrons, electrons are harder to get rid of. high electronegativity values and high ionization energy. 

What is the order of increasing bond strength?

Nonpolar,Polar,Ionic.

In a polar covalent bond what is happening?

Electrons are being shared unequally. The electrons are more attracted to the atom w the higher electronegative value which results in an unequal distribution of charge called a dipole. 

When is a bond nonpolar, polar and ionic.

Nonpolar: The electronegative difference equals 0.

Polar: The electronegative difference is between 0-2.0.

Ionic: Electronegative difference is higher than 2.0. In ionic bond the electron isn’t being shared.

Symmetric molecules are what? 

Nonpolar because the bond dipoles cancel. 

For molecular compounds how would you write them out? (Formula) 

Write symbol of first nonmetal followed by a subscript indicated by the prefix. Do NOT use charges. No ions in molecular compounds. 

For molecular compounds how would you write them out? (Name) 

Write name of first nonmetal with prefix indicating the number of the subscript. Then write name of second nonmetal with -ide ending and prefix indicating the subscript.