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Ch. 6: Chemical Bonding
Transcript of Ch. 6: Chemical Bonding
Richie, Javares, Martha, & Liz
pg.197-203 (Erica,Jalissa, Jeshua, Xavier
Molecular Geometry: pg.197-203
Jeshua, Jalissa, Xavier, & Erica
Keith, Samy, Wendy, & Pamela
Rodney, Antwuan, Daniella, & Michelle
Tarik, Nelrick, Brianna, & Tekoi
Ch. 6: Chemical Bonding
McKie - Pd. 1
Ionic compounds are formed by the bonding of non-metals to metals. Molecular Covalent which are really covalent compounds are usually liquids or gases, they are brittle and good insulators of heat. They are both composed of more than one element and is held together by some sort of electron interactions. Elements which are close together in electronegativity tend to form Ionic and Molecular compounds and can exists as a stable free molecules. Carbon Dioxide is a common example
Polyatomic Ion also known as a molecular ion is a Charged group of covalently bonded atoms. Polyatomic Ions combine with Ions of opposite chare to form ionic compounds. A polyatomic ion can often be considered as the conjugate acid / base of a neutral molecule. The prefix "poly-" means "many," in Greek, but even ions of two atoms are commonly referred to as polyatomic. Polyatomic ions are often useful in the context of acid-base chemistry or in the formation of Salts.
Stephanie, Jamie, Jalin, & Jamelia
Naming Binary Molecular Compounds
Cody, Jyrra, Nyjestic, & Dominic
''The Octet rule'' (pg 182-183
The Octet rule is basically chemical rule that states that atom of a low atomic number tend to combine in such way that they each have eight electrons in their valence shells which make them have the same electronic configuration a a noble gas
According to my research elements follow the octet rule because they always seek the most stable electron configuration . Following the octet rule results in completely filled s- and p- orbitals in an atom's outermost energy level
Exeption to the octet rule example : Hydrogen and helium are both very small these two atoms are most stable when their outermost electron shells are filled . Which means they only need a pair of electrons for maximal stability .This is why hydrogen is stable as ion , since helium is one of the noble gases it has a very low reactivity
-Formation of a Covalent Bond (Brianna J.)
The formation first starts when two atoms are separated and far in distance to the point they can't affect each other.
-Before they become close,both atoms contain one proton in the nucleus and an electron in the 1s orbital.
-As soon as they become closer to each other ,the nucleus and electrons become attracted and the potential energy decreases. But the total potential energy increase because the two nucleus are repelling.
-When the atoms first start to affect each other, the potential energy is lowered because the attraction between the electron and proton is stronger than the repelling of the like charges.
-As the electron and proton becomes more attracted to each other the total potential energy still decreases until the energy of the repelling charges is the same of the attraction between the electron and proton.
-After that happens the potential energy is at a minimal that forms a molecule of the two atoms and the potential energy is higher because the repulsion became stronger than the attraction.
Covalent bonding and molecular compounds
A molecule is a neutral group is a neutral group of atoms that are held together by covalent bonds.
A single molecule of a chemical is an individual unit capable of existing on its own. It may consist of two or more atoms as in water or sugar.
As the temperatures, the kinetic energy of the molecules also raises. This molecules segregate each other and begin the gas stage. To determine the allure between particles of a liquid, it's just necessary to see it's boiling mark. The greater the bonding point, the solid the forces between molecules. Intermolecular forces is the push of attraction between particles. They differ in strength but are usually more fragile, than bonds that get together with atoms in molecules.(page 203)-
Chemical compounds simplest units are molecules are called molecular compounds.
Compositions of compounds are given by its chemical formula.
Chemical formula indicates the relative numbers of atoms of each kind in a chemical compound by using atomic symbols and numerical subscripts.
Molecular formula shows the types and numbers of atoms combined in a single molecular of a molecular compound.
Example Of VSEPR Theory
VSEPR Theory: states that repulsion between the sets of valence-level
electrons surrounding an atom causes sets to drift apart
"Valence-Shell, Electron-Pair Repulsion"
Characteristics of the Covalent Bond ( Nelrick Duroseau)
Take a look at our project
- Covalent bonds are molecules.
- Covalent bonds have low melting and boiling points.
- They do not conduct electricity.
- Bond length is the average distance between two bonded atoms.
- Covalent bonds are formed by sharing of electrons.
- The shared pair of electrons is attracted by the nuclei of both of the atoms.
_ Covalent bonds are covalently bonded as long a heir their potential energy remains close to minimum
- To separate bonded atoms the same amount of energy must be added. .
Hydrogen bond is a weak bond between two molecules resulting from an electrostatic attraction between a proton in one molecule and an electronegative atom in the other. To form an hydrogen bond you need n, f, o and H have to bond with one of these molecules, water is the example of an hydrogen bond because
Two molecules of water can form a hydrogen bond between them; the simplest case, when only two molecules are present, is called the water.-
Some of the strongest intermolecular forces exist between polar molecules. They act like tiny dipoles because of their uneven charge distribution. "A
is created by equal but opposite charges that are separated by short distance," chem book, pg 204. A dipole is represented by an arrow with a head pointing to the negative pole (the bad guy) and a crossed tail that ends up on top of the positive pole (protecting the good guy). Opposite charges attract each other. The forces of attraction between polar molecules are known as
. The effect of this is reflected on the boiling points of the molecule. For molecules that contain more that two atoms, molecular depends on both the polarity of the orientation of each bond. -
London Dispersion forces are the intermolecular attractions resulting from the constant motion of electrons and the creation of instantaneous dipoles, Fritz London proposed their existence in 1930. London forces acts with all atoms and molecules, but they are the only intermolecular forces acting among noble-gas atoms and nonpolar molecules. London forces increases with increasing atomic or molar mass.-
• Hybridization are when orbital’s form hybrid orbital’s. Basically, orbitals are moved to form new identical orbitals.
One example of hybridization is single bonds, which is when atoms share electrons that hybridize. Also, lone pairs that hybridize.
How do you determine hybridization on any atom?
* You must identify the regions of high electron density
*To determine this region, you must find the single bonds of the atoms.
*. If an atom has 4 regions of high electron density, then it is classified as sp^3.
*For example, CH4 has 4 single bonds, so if would be sp^3. In the meanwhile, if an atom has 3 region of high electron density, it would be classified as sp^2.
*And for atoms with 2 regions of high electron density, it would be classified as sp.
VSEPR Theory And Molecular Geo. Chart
Used To Predict The shapes of polyatomic ions as well as molecules with double or triple bonds
Molecular compounds unlike ionic compounds are made up of individual covalently bonded units, (molecules).
There are two nomenclature systems used to name binary molecules
1. Stock Systems (newer system) requires an understanding of oxidation numbers.
2. Prefixes (older systems) uses prefixes to name molecular compounds
Tetrachloride | prefixes
tetra= 4 chloride atoms present in a single molecule of the compound.
Example 2: The two oxides of caron,
= monoxide &
= carbon dioxide.
mon from mono= 1 oxygen atom | di= 2 oxygen atoms
1 = mono 6 = hexa
2 = di 7 = hepta
3 = tri 8 = octa
4 = tetra 9 = nona
5 = penta 10 = deca
#'s prefixes #'s prefixes
A Comparison of Ionic and Molecular Compounds
The Metallic Bonding
Chemical bonding is different in metals than ionic, molecular, or covalent compounds. There is a difference between metals because there good electrical conductors.
The Metallic- Bond Chemical
The highest energy levels of most atoms are occupied by a few electrons. For example, the S-block has 1 or 2, The P-block can hold up to 6, and D-block occupy vacant orbitals. A vacant orbital in the outer energy level overlap. The overlapping of the orbitals allow them to roam free also called derocalized. The chemical bonding that results from the attraction between metal and the surrounding sea of electrons is called metallic bonding.
Metals are strong absorbers and reflectors of light because they have many orbitals that seperate small energy differences. Two metals that are easy to form into desired shapes are small malleability and ductility
-Malleability is the ability of a substance to be hammered or beaten into shape.
-Ductility is the ability to be drawn, pulled, or extruded through a small opening to produce a wire.
Metallic Bond Strength
Metallic bond strength depends om the nuclear charge and the number of electrons. These factors are reflected in a metals enthalpy of vaporization ( the amount of energy absorbed as heat when a specified amount of a substance vaporizes at a constant pressure. Some enthalpy of vaporization in metals are shown below.
Jeshua-Molecular geometry is the 3-Dimensional shape of a molecular bond resulting from the atoms and their electrons repelling from each other. To understand this you should have an understanding of the VSEPR Theory and the Lewis dot structure. For example, the bonding could result in a shape of linear, trigonal, tetra, etc. You could see the shapes of the bonds on the table
The force in ionic compounds are very strong between positive and negative charge. Forces between molecules are weaker than forces ionic bonding. The difference between the forces is the different properties in the two compounds. Melting points, boiling points and hardness varies in compound depending on the attraction. Molecular compounds have low melting points because of their weak attraction. For example , many molecular compounds are gaseous at room temperature. Ionic compounds are hard but brittle. The shift of a row of ions can cause an ionic compound to be brittle. (See image to the right) In a solid state the compounds aren't electrical conductors. In the molten state the freely moving ions carry electrical current. When in water, ionic compounds can dissolve. These ions become free when dissolved.
A polyatomic ion is a charged group of covalently bonded atoms. Certain atoms bond covalently to form a group of atoms that have molecular and ionic characteristics. Polyatomic ions combine with opposite charges. The charge of a polyatomic ion results from a negative charge or a positive charge.
Types of Chemical Bonding ( Te'Koi)
Bonding of Covalent Bonds
A chemical bond is a mutual attriction between the nuclei and the valance electrons of different atoms that bind the atoms together.
"Electron Dot Notation" (pg.184-185)
Electron-Dot notations is a helpful way to keep track of the atoms valence electrons
In electron-dot notations valence electrons are indicated by dots that surrounds an elements symbol, depending on how many valence electrons it has will depict how many dots to place around the element's symbol
An unshared pair(or lone pair) is a pair of electrons that are not involved in bonding and that belong to exclusively one atom
All of the elements and dots represents the Lewis Structure
When atoms come together their valence electrons are distributed in ways that makes the atoms more stable.
Bonding that results from the electrical attraction between cations and anions is called Ionic bonding.
Unlike when atoms join together by ionic bonding atoms come together by covalent bonding share electrons
Orbitals of equal energy and are produced by a combination of two or more orbitals on the same atom is called hybrid orbitals. The number of orbitals produced equals the number of orbitals. If an atom was to have 4 orbitals if 3 orbitals contains a pair of electrons and one contains unpaired electrons than the unpaired electron can form a single bond.
Bonding between atoms of two elements, ionic or covalent can be gauged by calculating the difference in their electronegativity
The hydrogen-hydrogen bond is a nonpolar-covalent bond, a covalent bond where the bonding electrons are shared equally by the bonded atom.
A polar-covalent bond is a covalent bond where the bonded atoms have an unequal attraction for the shared electrons.
Formation of Covalent Bonds
The linear geometry of molecules is possible since hybridization involve the "s" orbital and 1 available empty "p" orbital to hold the "sp" hybrid orbitals. The trigonal planar geometry of molecules is possible since hybridization involves the "s" orbital one singly occupied "p" orbital and one empty "p" orbital to hold the "sp^2" hybrid orbitals.
Naming Binary Ionic Compounds- Jalin
* Nomenclature- Naming system for binary ionic compounds
* The Cation(+) is given first then the Anion (-)
* Stock system of nomenclature is used to distinguish ions with different charges(Roman Numerals)
Binary Ionic Compounds
Binary Ionic Compounds- Chemical compounds that include two different elements, negative or positive, that must be equal which then leaves it electronically neutral. (anions - , cations +)
* Oxyanions-polyatomic ions containing oxygen
* Elements combine with oxygen to form more than one type of oxyanion
* Depending on how many oxygen atoms are in oxyanions, determines its name
When writing a Binary Ionic Compound formula the charges are not included.
* Ions with more oxygen atoms ends with -ate (nitrate)
* Ions with less oxygen atoms ends in -ite (nitrite)
* More than two types of oxyanions can be formed: Hypo-, -ite, -ate, and per-
* Hypo-, anion with one fewer oxygen atom than -ite anion
* Per-, anion with one more oxygen atom than -ate anion
The formula usually consists of a metallic and a nonmetallic ion.
* With multiple polyatomic ion, the formula for the polyatomic ion is enclosed in parentheses
*NaCl is an example of a binary ionic compound because Na is positively charged while Cl on the other is hand is negatively charged. So in that case they cancel each other out.
Notation is simply putting one dot around the chemical symbol for every valence electron (which where you point the dot outside that the element has). Using all four sides other chemical symbol. top bottom, left, and right. for the dot. And to be sure that each side has one dot before putting in a second dot on a side. For example , The chart that in page 184 in the top left corner the element that in the group have a number of valance electrons. Electron dot notation for Hydrogen would be a capital "H" and one dot either on top of the H, the bottom or either side. Also a pair of dot between the two symbols represent the shared pair of a covalent bond.
A Binary Ionic Compound is normally a salt.
The properties of molecules depend not only on the bonding of atoms but also on molecular geometry - the three dimensional arrangements
of a molecule's atoms in space
Crossing Over is a process used to balance the charges between ions in the compound and this method helps determine the subscripts in ionic compound formulas.
*Molecular Bond angles
*Orbitals that contain valence electrons
*If a Calcium ion is +2 and a Chloride ion is -1 then Calcium Chloride is written CaCl2.
Basically, the charge of a positive ion is written on the negative ion and the charge of the negative ion is written on the positive ion which then creates a "cross-over".
*Explaining The VSEPR Theory
Naming Binary Molecular Compounds
molecular compounds are made up of individual covalent bonds unlike ionic compounds.
There are two systems used to name molecular compounds. The newer one has to have an understanding of oxidation numbers.
The old system of naming molecules consisted of the use of prefixes.
Example: the molecular compound CCL4 is named Carbon Letrachloride the prefix letra- indicates that the four chloride atoms are present in a single molecule of the compound.
Acids & Salts
An acid is a type of molecular compound
The two main ones are Binary and Oxyacids
Binary acids consist of two elements - usually a halogen and hydrogen
Oxyacids contain hydrogen, oxygen, and a third element that's usually a nonmetal.
Polyatomic ions are produced by the loss of hydrogen atoms from oxyacids.
An examples of oxyacids and oxyonions are sulfuric acid, nitric acid, and phosphoric acid.
A salt is an ionic compound composed of a caution and the anion from the hydrochloric acid.
Calcium sulfate is a salt containing an anion from sulfuric acid.
some salts contain anions in which one or more hydrogen atoms are contained.
These are named by the word hydrogen or prefix bi-.
An ionic compound is composed of positive and negative ions that are combined so that the numbers of positive and negative charges equal. Most ionic compounds exist as crystalline solids. A crystal of any ionic compound is a three-dimensional network of positive and negative ions mutually attracted to one another. In contrast to a molecular compound , an ionic compound is not composed of independent , neutral units that can be isolated and examined.
The chemical formula of an ionic compound merely shows the ratio of the ions present in a sample of any size. The ratio of ions in a formula unit depends on the charge of the ions combined.
Lewis structures are formulas in which atomic symbols represent nuclei and inner shell electrons, dot pairs, or dashes between two atomic symbols represent electron pairs in covalent bonds, and dots adjacent to only one atomic symbol represent unshared electrons. A structural formula indicates the kind number and arrangement and bonds but not the unshared pairs of electrons in the molecule. For example F-F and H-CI- are structural formulas