Combinations of Atoms
description
Transcript of Combinations of Atoms
![Page 1: Combinations of Atoms](https://reader036.fdocuments.us/reader036/viewer/2022070501/56816939550346895de0a5e5/html5/thumbnails/1.jpg)
Combinations of Atoms
Chapter 8.2
![Page 2: Combinations of Atoms](https://reader036.fdocuments.us/reader036/viewer/2022070501/56816939550346895de0a5e5/html5/thumbnails/2.jpg)
Compounds
1.Compoundsa.Elements are rarely found pure in the
earth, they are generally found as compounds.
b.A compound is a substance that results when the atoms of two or more elements are chemically combined.
![Page 3: Combinations of Atoms](https://reader036.fdocuments.us/reader036/viewer/2022070501/56816939550346895de0a5e5/html5/thumbnails/3.jpg)
Compounds
i.The result is a new substance with properties different from those of elements that compose it.
ii.Example: Water is a compound formed from the atoms of hydrogen and oxygen.
![Page 4: Combinations of Atoms](https://reader036.fdocuments.us/reader036/viewer/2022070501/56816939550346895de0a5e5/html5/thumbnails/4.jpg)
Compounds
a.A molecule is the smallest complete unit of a compound. Water is formed from two hydrogen molecules and one oxygen molecule. H-O-H
b.Diatomic molecules are molecules that exist naturally as two atoms.
![Page 5: Combinations of Atoms](https://reader036.fdocuments.us/reader036/viewer/2022070501/56816939550346895de0a5e5/html5/thumbnails/5.jpg)
Compounds
i. Hydrogen atoms always exist naturally as a diatomic molecule.
ii.The oxygen atoms you breath are O2 atoms.
![Page 6: Combinations of Atoms](https://reader036.fdocuments.us/reader036/viewer/2022070501/56816939550346895de0a5e5/html5/thumbnails/6.jpg)
Energy Levels
1.Energy Levelsa.Energy levels are the arrangement of
electrons within the electron cloud of an atom; they are also the specific energies an atom can have.i.Atoms have a specific number of energy
levels to contain the amount of electrons they have.
![Page 7: Combinations of Atoms](https://reader036.fdocuments.us/reader036/viewer/2022070501/56816939550346895de0a5e5/html5/thumbnails/7.jpg)
![Page 8: Combinations of Atoms](https://reader036.fdocuments.us/reader036/viewer/2022070501/56816939550346895de0a5e5/html5/thumbnails/8.jpg)
Energy Levels
a.The electrons in an atom travel on the energy levels in a set of “paths” called orbitals. i.An orbital is the region of space in the energy level where an electron is likely to be found.
![Page 9: Combinations of Atoms](https://reader036.fdocuments.us/reader036/viewer/2022070501/56816939550346895de0a5e5/html5/thumbnails/9.jpg)
![Page 10: Combinations of Atoms](https://reader036.fdocuments.us/reader036/viewer/2022070501/56816939550346895de0a5e5/html5/thumbnails/10.jpg)
Energy Levels
The following table describes the energy levels, orbitals, and # of electrons.Energy Level Operation Orbital Operation # of Electrons
1 X Self 1 X 2 2
2 X Self 4 X 2 8
3 X Self 9 X 2 18
4 X Self 16 X 2 32
![Page 11: Combinations of Atoms](https://reader036.fdocuments.us/reader036/viewer/2022070501/56816939550346895de0a5e5/html5/thumbnails/11.jpg)
Energy Levels
a.When electrons are in their highest energy levels the atom is said to be in an excited state.
b.When electrons are in their lowest energy levels the atom is said to be in a ground state.
![Page 12: Combinations of Atoms](https://reader036.fdocuments.us/reader036/viewer/2022070501/56816939550346895de0a5e5/html5/thumbnails/12.jpg)
Energy Levels
a.Atoms with filled energy levels are stable and do not react. This group of elements is the “Noble Gases”.i.Elements that are near the edges of the
period table are the most reactive, because they are closest to having a complete set of electrons.
ii.Elements nearest the bottom are also more reactive because they have more energy levels.
![Page 13: Combinations of Atoms](https://reader036.fdocuments.us/reader036/viewer/2022070501/56816939550346895de0a5e5/html5/thumbnails/13.jpg)
Chemical Bonds
1.Chemical Bondsa.A chemical bond is produced by the
interaction of valence electrons (electrons in the outermost energy) and is the force that holds atoms together.
b.Atoms can form chemical bonds by either sharing electrons or transferring electrons from one atom to another.
![Page 14: Combinations of Atoms](https://reader036.fdocuments.us/reader036/viewer/2022070501/56816939550346895de0a5e5/html5/thumbnails/14.jpg)
Ionic Bonds
a.An ionic bond is a bond formed through the transfer of electrons from one atom to another. i.When an ionic bond is formed, both atoms
become either positively or negatively charged and are called ions.
ii.An ion is an atom or group of atoms that carry a charge.
![Page 15: Combinations of Atoms](https://reader036.fdocuments.us/reader036/viewer/2022070501/56816939550346895de0a5e5/html5/thumbnails/15.jpg)
Ionic Bonds
i.When an atom gives away electrons the atom becomes positively charged and is called a cation.
ii.When an atom gains electrons the atom becomes negatively charged and is called an anion.
![Page 16: Combinations of Atoms](https://reader036.fdocuments.us/reader036/viewer/2022070501/56816939550346895de0a5e5/html5/thumbnails/16.jpg)
![Page 17: Combinations of Atoms](https://reader036.fdocuments.us/reader036/viewer/2022070501/56816939550346895de0a5e5/html5/thumbnails/17.jpg)
Covalent Bonds
1.Covalent Bondsa.A covalent bond is a bond between atoms
that share electrons.b.When electrons are shared in a diatomic
molecule the nuclei of each atom pull on the electrons with the same force and create a neutral molecule.
![Page 18: Combinations of Atoms](https://reader036.fdocuments.us/reader036/viewer/2022070501/56816939550346895de0a5e5/html5/thumbnails/18.jpg)
Covalent Bonds
a.When electrons are shared in a molecule of different elements the electrons are shared unequally.i.For example, in a water molecule the two
oxygen molecules pull on the electrons greater than the one hydrogen molecule which gives the molecule a slightly positive charge at its hydrogen end and a slightly negative charge at its oxygen end.
![Page 19: Combinations of Atoms](https://reader036.fdocuments.us/reader036/viewer/2022070501/56816939550346895de0a5e5/html5/thumbnails/19.jpg)
![Page 20: Combinations of Atoms](https://reader036.fdocuments.us/reader036/viewer/2022070501/56816939550346895de0a5e5/html5/thumbnails/20.jpg)
Chemical Formulas
1.Chemical Formulasa.A chemical formula is symbols indicating the
elements a compound contains and the relative number of each element.
i. In a compound the number of elements in the same compounds are always found in the same proportion.
ii.For example, the chemical formula for water is H2O, which represents two hydrogen atoms and one oxygen atom for every H2O molecule.
![Page 21: Combinations of Atoms](https://reader036.fdocuments.us/reader036/viewer/2022070501/56816939550346895de0a5e5/html5/thumbnails/21.jpg)
Mixtures
1.Mixturesa.A mixture is material that contains
two or more substances that are not chemically combined. i.The substances in a mixture keep their
individual properties, and can be separated by a physical means.
![Page 22: Combinations of Atoms](https://reader036.fdocuments.us/reader036/viewer/2022070501/56816939550346895de0a5e5/html5/thumbnails/22.jpg)
Solutions
a.A solution is a mixture in which one substance is uniformly dispersed in another substance. i.An example of a solution is Kool-Aide. The
sugar is completely dissolved in the water.ii.Not all solutions are liquids. Gases and solids
can also form solutions. iii.An alloy is a solution of two or more metals,
such as brass (Cu & Zn) and bronze (Cu & Sn).