Bonding Options

Bonding Options

by Mike Martz

​First, an important concept...

​Anything with charge will exert a force on other charges. Like charges repel while opposite charges attract. This force acts through space, no contact is needed.

​Now, a HUGE important problem/question...

​If the model of the atom looks like we've been discussing, then how can the universe have anything but just separate atoms? The outside of every atom is layers of negative electrons... if one atom came near another one, wouldn't the negative electron shells repel the other atom? How can atoms "stick" together to build compounds, molecules, etc...?

​<--- Repelling Force? --->

Let's Dive Deeper

And Figure This Out!​

​

Multiple Choice

Before we start explaining anything deeper... which is a correct statement about electric force?

• If electrons touch each other they can repel one another.

• Opposite charges repel.

• Negative charge repels other negative charge through space.

• Only positive charges repel.

​Okay, Now Let's Go Deeper....

​Our question is "how can one atom 'stick' to another atom... it seems like they should repel due to electric force?"

The key to the answer comes from the trends we've been exploring on the periodic table.

• Columns on the periodic table have the same number of valence electrons (except for the middle block of metals).

• Noble Gases are a unique column because they are non-reactive/stable and have a full valence shell.

• The "metals" have 1, 2, or 3 valence electrons and have a weak hold on those electrons.

• The "nonmetals" have a nearly-full valence shell and have a strong hold on their electrons.

• Due to this, we consider nonmetals "gainers" since they typically attract 1, 2, or 3 more electrons which fills their valence shell... and, we consider metals "losers" since they typically lose their 1, 2, or 3 valence electrons leaving the full shell(s) below.

• ​In both cases, there is a trend that atoms "prefer" or "tend to get" a "full valence shell."

Multiple Choice

What makes the noble gases unique?

• They're the only gases on the periodic table.

• They have a full valence shell.

• Nothing else on the periodic table has that name.

• They have an empty valence shell.

Multiple Choice

Since noble gases have a full valence shell, they have a unique behavior... which is...

• Atoms of the Noble Gases are stable; they don't react or bond with other atoms.

• They are highly reactive... even explosive.

• Their electron numbers form a Fibonacci sequence.

Multiple Choice

All the metals on the period table...

• Have a weak hold on their 1, 2, or 3 valence electrons

• Have a nearly-full valence shell

• Will react with the Noble Gases

• Don't have any valence electrons

Multiple Choice

All the nonmetals on the periodic table have a nearly-full valence shell and thus have a strong hold on their electrons. We also call them "gainers" because they tend to...

• Gain prtons through fusion

• Gain mass by forming isotopes

• Lose the 4, 5, 6, or 7 valence electrons that they have

• Attract 1, 2, 3, or 4 more electrons which fills their valence shell

​Simplification

​The entire periodic table can be broken into three broad areas:

1. ​Metals - lose their few valance electrons

2. ​Nonmetals - gain a few valence electrons

3. Noble Gases - stable/nonreactive and don't form bonds

​

​Therefore, if we are asking how atoms could interact with others, there are only three options:

​

​- Metals with Nonmetals - Nonmetals with nonmetals - Metals with metals

​

​Since Noble gases don't react or appear in compounds, it isn't necessary to include them.

​1st - Metals with Nonmetals

• ​Nonmetals attract e- (to fill valence shell)

• ​Metals weakly hold their valence e-

• ​Nonmetals gain e- from the metals which lose e-

• ​Nonmetals now have more "-" so they are "- ions"

• ​Metals now have less "-" so they are "+ ions"

• The gain and loss of electrons is why these atoms are now ions.​

• Opposite charges attract... an IONIC BOND

• ​Ex: NaCl (table salt)

Multiple Choice

An "ionic bond" is named that way because ions are formed from the gaining/losing of electrons between metals and non-metals.  Which of the following is NOT an ionic compound?

• $$Li_2O$$  

• $$CO_2$$  

• $$CaS$$  

• $$CaCl_2$$  

Multiple Choice

Which is the correct reason that atoms "stick together" in an ionic bond?

• Atoms are just like tiny magnets... if they get close enough, a bond will form

• Metals like to gain electrons from non-metals

• Non-metals need to gain other atoms to be stable

• The gain/lose of electrons gives the atoms opposite charges... opposite charges attract

• ​Nonmetals have an attraction for additional electrons to fill their valence shell. They want to gain electrons.

• ​If more than one nonmetal is present, they would have an attraction for each other's valence electrons. This attraction pulls them together.

• ​This "bond" can be between two atoms (like HCl below) or even more (like H₂O below).

• ​When these nonmetals "share" electrons, each atom involved is essentially "more full" of valence electrons than before. Since bond is basically due to sharing valence electrons, it is called a Covalent Bond (co = share valent = valence e-).

​2nd - Nonmetals with Nonmetals

Multiple Choice

A covalent bond is named that way because it is a "sharing electron" ("co" "valence") bond that forms between gainers.  Which of the following does NOT have a covalent bond?

• $$H_2O$$  

• $$CH_4$$  

• $$Cl_2$$  

• $$MgCl_2$$  

Multiple Choice

Which is the correct reason atoms stick together in a covalent bond?

• One atom takes another atoms electrons and the opposite charges holds them together.

• Both atoms desire more electrons to fill their valence shell; the mutual attraction for each other's electrons holds them together.

• Since both atoms are losers they lose electrons to each other and their similar "+" charge bonds them.

• Since both atoms are gainers they both gain electrons and their similar "-" charge holds them together.

​3rd - Metals with metals

• ​Metals "prefer" to lose their 1, 2, or 3 valence electrons to have a full shell underneath. So it might seem that metal atoms would have nothing to do with other metal atoms. However, think of all the metal structures there are... metal atoms must attract!

• We imagine that in a metal, the atoms are constantly trading electrons and those momentary charges that occur when trading is what holds it all together.

• Even a small metal object like a paper clip, there are trillions of trillions of atoms and all those little attractions add up. Futhermore, this helps explain how metals can be bent as well as why metals conduct electricity

• We call this "metallic bonding" but it is different than ionic or covalent because there's really no formula unit (like H₂O or NaCl); in a metal is just a sea of atoms trading electrons.

Multiple Choice

Which is a correct statement about how the atoms in metal objects hold together?

• One metal atom is a loser and the other is a gainer so they make an ionic bond.

• Metal atoms share electrons and that holds them together.

• Metals are constantly trading electrons and that makes momentary charges that attract.

• Nonsense, metals are losers so they don't attract at all.

Identifying Bonds

You can tell if a substance is ionic, covalent, or metallic simply by looking at the atoms that make up the substance.

• Metal with nonmetals... it has to be ionic

• Nonmetals only... it has to be covalent

• Metals only... it has to be metallic

Multiple Choice

Which of the following would have an ionic bond?

• Carbon dioxide

• Magnesium chloride

• Hydrogen sulfide

• Titanium alloy

Multiple Choice

Which of the following is NOT an ionic bond?

• $$KCl$$

• $$MgBr_2$$

• $$HCl$$

• $$LiF$$

Multiple Choice

Which of the following has a covalent bond?

• Potassium Oxide

• Sodium Sulfide

• Carbon Dioxide

• Aluminum alloy

Drag and Drop

When a "metal" is bonded to a "nonmetal" the bond will be​

Placeholder

When multiple "nonmetals" are bonded, the bond will be​

Placeholder

When multiple "metals" are "bonded" in a group, the "bond" is called​

Placeholder

Drag these tiles and drop them in the correct blank above

Ionic

covalent

metallic

divalence

mutagenic