CP Sci 9- 1st Sem.
Gen Chem - 1st Sem.
Matter and Atoms
1. Identify the characteristics of matter.
2. Compare the particles that make up atoms of elements.
3. Describe three types of chemical bonds.
Matter can be described as anything having mass and volume. Matter can be better defined, though, by separating it into its simplest parts. Since the atom is the basic unit of matter, we will start there. A group of similar atoms is called an element. Here are some elemental facts.
Atoms are the smallest particle of an element retaining all of its properties. Though, invisible to the eye and microscope (limited images are possible with the tunneling microscope), you could theorize that an atom of gold would have the same luster and texture (look and feel) as a solid gold bar. The belief in atoms as the basic building block of matter dates back o the Greek philosophers (450 BC) when Democritus first proposed the existence of atomos (small particles of matter). Unfortunately Democritus' views were not accepted until the early 1700s.
Atoms are made of even smaller subatomic particles called protons, neutrons, and electrons.
Combinations of elements can form compounds. Its important to know that compounds are pure substances. (A compound of H2O contains nothing but H2O.) Here are some facts regarding compounds.
The atomic numbers indicated on the periodic table indicate the number of protons in the nucleus.
Whenever an atom gains or looses electrons it becomes an ion. You can find the net charge of the atom by subtracting the number of electrons from the atomic number.
Most elements in the first two rows of the periodic table have at least two known isotopes. Isotopes have the same number of protons and electrons but differ in the number of neutrons. (mass - protons = neutrons)
Example: hydrogen-1 hydrogen-2 hydrogen-3
The distribution of electrons in the different electron orbitals is called the electron configuration. The distribution within the energy levels (n) and suborbitals follows the following principles.
1) Electrons always fill the available suborbitals based on the suborbital's energy levels (s,p,d,f).
the outermost energy level (shell) is holding the maximum number of electrons
the atom is
OF CHEMICAL BONDS
Ionic bonds & Compounds:
Ionic bonds are formed from the transfer of electrons from one atom to another. The Ionic bond that forms is the result of the attraction of oppositely charged ions (atoms). The attraction acts much like the opposite poles of a magnet. Here are some simple rules for ion formation and naming.
Though we have learned about the forming of bonds through the transfer of electrons, the majority of compounds that we come in contact with in our daily lives are formed in a completely different manner. The difference is that these atoms are covalently bonded.
A covalent bond is one where the electrons are shared. A group of covalently bonded atoms is called a molecule. These molecular substances include DNA, sugar and carbon dioxide. The molecules can contain as few as 2 atoms and as many as a million. Rules for covalent bonds:
Last modified: September 05, 2004