Lesson 1.1: The Structure of Matter Part 2
Completion requirements
Unit A: Chemical Change
Lesson 1.1: The Structure of Matter
Describe why atoms bond together
Give to ways that atoms fill their outermost energy levels.
Now that you have reviewed the structure of the atom and can draw them, you can more readily understand why atoms combine to form molecules or compounds. Atoms want to exist at there lowest energy level, which is where they are the most stable. They are at the lowest energy level when the outermost energy level is full. Remember the levels are full with 2, 8 and 8 electrons (for the first 20 elements)
This explains why Noble gases do not chemically react. They do not need to combine with other atoms because their outermost energy levels are already full.
Read pages 12 and 13. Try the activities and view the videos below if need be, but it is not required.
There are two ways that atoms can fill their outermost energy levels.
- Atoms can gain or lose electrons. This is described as a transfer of electrons. Neutral atoms do not really exist in nature (except the Noble gases). Atoms will lose or gain atoms and exist with their outermost energy level full. When to number of protons is not equal to the number of electrons the 'atoms' exist as ions.
- Atoms can share electrons. This sharing is done by two or more nonmetals.
Instructions
Click all the boxes. Grab electrons from the metals and transfer them to the nonmetals until the metals have no electrons and the non metals have 8 electrons (full energy levels). This is simple when the ratio of metals to nonmetals is 1 to 1.
Sometimes the ratio will not be 1 to 1. This will make the process trickier. You will know you have done it correctly when the total charge on the metals is equal to the total charge on the nonmetals... or just click the check button.
Click all the boxes. Grab electrons from the metals and transfer them to the nonmetals until the metals have no electrons and the non metals have 8 electrons (full energy levels). This is simple when the ratio of metals to nonmetals is 1 to 1.
Sometimes the ratio will not be 1 to 1. This will make the process trickier. You will know you have done it correctly when the total charge on the metals is equal to the total charge on the nonmetals... or just click the check button.
Instructions
Click the box. Share electrons by clicking and dragging them to another atom. Remember each atoms needs 8 electrons orbiting (except for hydrogen with needs two) Click the check button to see if you are correct. Notice the Lewis diagram. (NOTE: You will not be tested on Lewis diagrams for compounds, but this activity is useful for helping yo understand what is going on.)
Click the box. Share electrons by clicking and dragging them to another atom. Remember each atoms needs 8 electrons orbiting (except for hydrogen with needs two) Click the check button to see if you are correct. Notice the Lewis diagram. (NOTE: You will not be tested on Lewis diagrams for compounds, but this activity is useful for helping yo understand what is going on.)
These videos have a little more information than needed but again demonstrate transfer and sharing of electrons.
Atoms combine to be at their lowest energy level, which is when their outermost energy level is full (2 or 8 electrons).
Atoms will fill their outermost energy level by sharing or transferring electrons. Sharing happens between nonmetals. Transfers happen between a metal and a nonmetal.
Atoms that have a different number of electrons, compared to protons, are ions. An atom with a positive charge is a cation, and one with a negative charge is an anion.
Atoms will fill their outermost energy level by sharing or transferring electrons. Sharing happens between nonmetals. Transfers happen between a metal and a nonmetal.
Atoms that have a different number of electrons, compared to protons, are ions. An atom with a positive charge is a cation, and one with a negative charge is an anion.
Science 20 Textbook, Courtesy of Alberta Education