6.1 Elements Combine to from Compounds Compounds form when two or more different atoms combine....

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6.1 Elements Combine to from Compounds Compounds form when two or more different atoms combine. Properties of compounds depend on which atoms are in the compound and how the atoms are arranged. Properties of compounds are different than that of just elements that make them up. Ex) Water is made out of Hydrogen and Oxygen, and H and O are both colorless gas at room temperature. But when these two elements make a compound, they are liquid at room temperature.

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Transcript of 6.1 Elements Combine to from Compounds Compounds form when two or more different atoms combine....

Page 1: 6.1 Elements Combine to from Compounds Compounds form when two or more different atoms combine. Properties of compounds depend on which atoms are in the.

6.1 Elements Combine to from Compounds

Compounds form when two or more different atoms combine.

Properties of compounds depend on which atoms are in the compound and how the atoms are arranged.

Properties of compounds are different than that of just elements that make them up.Ex) Water is made out of Hydrogen and Oxygen, and H

and O are both colorless gas at room temperature. But when these two elements make a compound, they are liquid at room temperature.

Page 2: 6.1 Elements Combine to from Compounds Compounds form when two or more different atoms combine. Properties of compounds depend on which atoms are in the.

Compounds always contain atoms with a specific ratio.Ex) Ammonia (NH3)has a 3:1 (3 to 1) ratio of

hydrogen to nitrogenIf this ratio was different, we would not have

ammonia anymore. For example if we had a 1:3 ratio of hydrogen to nitrogen we would not have a compound called Hydrazoic Acid (HN3).

Ammonia (NH3)Hydrazoic Acid (HN3)

Page 3: 6.1 Elements Combine to from Compounds Compounds form when two or more different atoms combine. Properties of compounds depend on which atoms are in the.

Chemical formulas like that for ammonia, NH3, uses the chemical symbols for the element to represent the atoms in a compound.Ex) Carbon dioxide has one carbon and two

oxygens in it.Step 1: Find the chemical symbols for the elements

Carbon—C Oxygen—O Write these side by side–CO

Step 2: To show that there are two oxygens, you must write a “2” by it on the right in a subscript.

Step 3: Now you have your compound—CO2

Page 4: 6.1 Elements Combine to from Compounds Compounds form when two or more different atoms combine. Properties of compounds depend on which atoms are in the.

Counting Atoms

Directions:

1. Write down the different elements in each compound.

2. Write down how many of that particular atom there are

3. How many atoms are there total in the compound.

2 H2SO4   2 Mg(SO)4

Page 5: 6.1 Elements Combine to from Compounds Compounds form when two or more different atoms combine. Properties of compounds depend on which atoms are in the.

1) CH4 2) 4 HNO3

3) 4 Mg(OH)2 4) MgCl2

5) 4 Li2O 6) (NH4)3PO4

Page 6: 6.1 Elements Combine to from Compounds Compounds form when two or more different atoms combine. Properties of compounds depend on which atoms are in the.

1. Atoms bond because they want to be ________________.

2. Atoms are _____________ when they have ___ electrons in the outer shell. (Octet Rule)

3. In order to get ___ electrons in the outer shell, atoms _________, _________ or__________ electrons with/from other atoms.

4. The 18th Group, the _______________are already stable.

Stable

Stable

88

sharetakegive

Bonding and Valence Electrons

Noble Gases

Page 7: 6.1 Elements Combine to from Compounds Compounds form when two or more different atoms combine. Properties of compounds depend on which atoms are in the.

Valence Electrons

Electrons in the outer shell are called _________________electrons

____________________ are the electrons responsible for bonding two atoms together

Noble gases are stable because they have ____ valence electrons; all other atoms want the stability that noble gases have

valence

Valence electrons

8

Page 8: 6.1 Elements Combine to from Compounds Compounds form when two or more different atoms combine. Properties of compounds depend on which atoms are in the.

The number of Valence electrons can be determined by the number of the ___________

Group #1 has ____ valence electron; Group #2 has ____ valence electrons;

Group #17 has ____ valence electrons

Valence Electrons (Continued)

Chlorine—Halogen Sodium—Alkali Metal

group

12

7

Page 9: 6.1 Elements Combine to from Compounds Compounds form when two or more different atoms combine. Properties of compounds depend on which atoms are in the.

Ionic Bonding NotesIons are formed when atoms ______________ or

____________ electrons___________ electrons makes a positive ion___________ electrons makes a negative ion

Metals lose electrons to have ___ electrons in their outer shellNonmetals ______ electrons to have 8 electrons in their outer

shell.

gain lose

Losing

Gaining

8

gain

Page 10: 6.1 Elements Combine to from Compounds Compounds form when two or more different atoms combine. Properties of compounds depend on which atoms are in the.

Ionic Bonding

Ionic bonds form when there is an attraction between positive and negative ions.

We know that the Alkali Metals like to form positive ions (lose e-), and the Halogens like to form negative ions (gain e-).

This means that if Sodium (Na) loses an electron, Chlorine (Cl) will pick it up. We now have a sodium ion (Na+) and a chloride ion (Cl-).

These opposite charges will attract one another and they will bond and this is called an ionic bond.

Page 11: 6.1 Elements Combine to from Compounds Compounds form when two or more different atoms combine. Properties of compounds depend on which atoms are in the.

Ionic Bonding (Continued)

Chlorine

Chlorine, a nonmetal, makes a negative ion

Sodium

Sodium, a metal, makes a positive ion

OPPOSITES ATTRACT

Page 12: 6.1 Elements Combine to from Compounds Compounds form when two or more different atoms combine. Properties of compounds depend on which atoms are in the.

Naming Ionic CompoundsThe name for the positive ion stays the same from the

atom from which it was formed.The name for the negative ion is formed by dropping the

last part of its name and adding the suffix “–ide” to it.To complete the name of the compound put the positive

ion first followed by the negative ion.Ex) Table salt

Na+ and Cl- come together to form NaClNa+ is now “sodium”Cl- was chlorine, but since it is the negative ion it

changes to “chloride”Result: sodium chloride

Page 13: 6.1 Elements Combine to from Compounds Compounds form when two or more different atoms combine. Properties of compounds depend on which atoms are in the.

Covalent BondsA __________is a pair of shared electrons

between two atoms that are________.When forming covalent bonds, neither

atom ______or _____ electrons, so no ion is formed.

Covalent bonds are often represented by a line between two atoms. Most common is the ball-and-stick model.

covalent bond

nonmetals

gains loses

Page 14: 6.1 Elements Combine to from Compounds Compounds form when two or more different atoms combine. Properties of compounds depend on which atoms are in the.

Covalent Bonds (cont.)The number of covalent bonds that an atom

can make depends on the number of ____________that it has.Ex) The Halogens (Group 17) and Hydrogen only

have ___valence electrons. This means that they can only form one covalent bond.

Ex) The atoms in Group 16 have ___ valence electrons. This means that they can from two covalent bonds.Remember that all atoms want to be stable and have

____valence electrons.Ex) The atoms in Group 15 ( 5 valence e-) can form

______covalent bonds.Ex) The atoms in Group 14 (4 valence e-) can from

______ covalent bonds.

Valence electrons

7

6

8

three

four

Page 15: 6.1 Elements Combine to from Compounds Compounds form when two or more different atoms combine. Properties of compounds depend on which atoms are in the.

Covalent Bonds (cont.)Ex) Methane, CH4, can form _____

covalent bonds because carbon has ____ valence electrons. These are all single bonds because carbon is sharing only _____ pair of electrons with each hydrogen.

four

four

one

Page 16: 6.1 Elements Combine to from Compounds Compounds form when two or more different atoms combine. Properties of compounds depend on which atoms are in the.

Double BondsWhen atoms share more than one pair of

valence electrons, a _________can from.A double bond forms when ________ of

valence electrons are shared.Ex) The carbon atom in carbon dioxide,

CO2, forms double bonds with each _________ atom.

double bond

two pairs

oxygen

Page 17: 6.1 Elements Combine to from Compounds Compounds form when two or more different atoms combine. Properties of compounds depend on which atoms are in the.

Triple BondsA triple bond forms when an atoms share

____ pairs of valence electrons.Ex) Two nitrogen atoms can because they

have 5 valence electrons each atom, and they want 8.Because they want to get to 8, they each share

3 valence electrons. This results in the two nitrogen atoms sharing ____electrons, or three pairs.

N N

three

6

Page 18: 6.1 Elements Combine to from Compounds Compounds form when two or more different atoms combine. Properties of compounds depend on which atoms are in the.

A group of atoms held together by covalent bonds is called a________.

Molecules can have anywhere from two to _________of atoms in them.

Some molecules have only atoms of one element.These are called _______molecules.H2, N2, O2, F2, Cl2, Br2, and I2

molecule

thousands

diatomic

Page 19: 6.1 Elements Combine to from Compounds Compounds form when two or more different atoms combine. Properties of compounds depend on which atoms are in the.

Polar Covalent BondsIn a iodine (I2) molecule, both atoms are the

same and the shared electrons are attracted equally to both nuclei.

If the two atoms involved in a covalent bond are __________then some electrons will be attracted to one nucleus more than the other.

A covalent bond in which the electrons are shared unequally is called a ______________. Remember that “polar” means that something has

to extremes, like a magnet with to opposite poles.

very different

Polar covalent bond

Page 20: 6.1 Elements Combine to from Compounds Compounds form when two or more different atoms combine. Properties of compounds depend on which atoms are in the.

Polar Covalent Bonds (cont.)In a water molecule (H2O), the oxygen atom

attracts electrons more strongly than hydrogen atoms do. Because oxygen has eight protons in its nucleus

and the hydrogen only has one proton, the oxygen pulls electrons stronger towards it. This means that the oxygen side has a slightly negative charge and the hydrogen side has a slightly positive charge.

Page 21: 6.1 Elements Combine to from Compounds Compounds form when two or more different atoms combine. Properties of compounds depend on which atoms are in the.

Ionic Compounds

Most ionic compounds have a regular crystal structure.

Their structures depend on the ratio of their atoms and the sizes of the ions that make them up.

Page 22: 6.1 Elements Combine to from Compounds Compounds form when two or more different atoms combine. Properties of compounds depend on which atoms are in the.

Covalent CompoundsUnlike ionic compounds, _______ compounds can

exist as individual molecules.Chemical bonds give each molecule a specific,

three-dimensional shape called its ________ structure.

Molecular structure can influence how a ________ interacts with other substances.

Molecular structure can also affect how we detect them or how our bodies respond to them.Molecules with certain shapes will fit into certain

receptors in our nose that we can smell.Some drugs work while other don’t because specific

receptors in the body only allow certain shapes to fit.

covalent

molecular

molecule

Page 23: 6.1 Elements Combine to from Compounds Compounds form when two or more different atoms combine. Properties of compounds depend on which atoms are in the.

Lewis Dot StructuresThese depend on the number of valence

electrons. These are the outer-most electrons.

Page 24: 6.1 Elements Combine to from Compounds Compounds form when two or more different atoms combine. Properties of compounds depend on which atoms are in the.

polar covalentbond

ionic bond


Naming Compounds and Writing Formulas. Key Question: Why Do Atoms Combine In Certain Ratios?

Naming Compounds and Writing Formulas. Key Question: Why Do Atoms Combine In Certain Ratios?

Atoms Molecules and Compounds

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Compounds Atoms have a tendency to combine and form new materials. A bond is a kind of glue that holds atoms together to form new particles of a compound.

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atoms. Bonds - Amphitheater Public Schools€¦ · An atom’s structure affects ... atoms. SECTION 1 Why do atoms combine? Main Idea When atoms combine, they become more stable.

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Elements, Atoms, and Ions€¦ · 4. Atoms of one element can combine with atoms of other elements to form compounds. A given compound always has the same relative numbers and types

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IGCSE Chemistry - Atoms, Elements and Compounds

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Molecular Compounds. Molecular Compound atoms of non-metals combine and form a pure substance example: nitrous oxide (N 2 O) the atoms are joined by covalent.

Molecular Compounds. Molecular Compound atoms of non-metals combine and form a pure substance example: nitrous oxide (N 2 O) the atoms are joined by covalent.

Combinations of Atoms September 3, 2009. Compounds When the atoms of more than one element combine, they form a compound. Examples: Water (H 2 0)= 2 Hydrogen+

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Chapter 2: Molecules, Ions, and Compounds MACROSCOPIC SCALE Elements combine to make compounds. ATOMIC SCALE Atoms combine to make molecules, or extended.

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Chapter 3 Biochemistry. I. Carbon Compounds Inorganic vs. Organic Inorganic compounds do not contain carbon atoms Organic compounds contain carbon atoms.

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Heterocyclic Compounds. Heterocyclic Compounds contain ring made up of carbon atoms and another kind of atoms. (most commonly N, O, S) Homocyclic Compounds.

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Chapter 4 Atoms, Ions, and Compounds. The Composition of Compounds The law of multiple proportions states that the masses of element Y that combine with.

Chapter 4 Atoms, Ions, and Compounds. The Composition of Compounds The law of multiple proportions states that the masses of element Y that combine with.