Cation ions- elements with a positive charge in the periodic table. In addition to positive elements, there are also transition elements which can have two different positive charges.
Anions- elements with negative charges in the periodic table. There are no transition elements in the category of anions.
Ionic Compounds- Formed by a metal and a nonmetal. You write ionic compounds with the metal in front. An easy way of knowing if an element is a metal or not is by looking at the periodic table. There is a section that is divided off by a line which tells you which elements aren't metals. Here is an example of the table.
Another factor we had to learn is knowing how to name ionic elements that form multiple ions. Here is a photo of elements that can have multiple ions. Looking at this table, it was very easy to comprehend how to name the elements with multiple charges. When we were going through the problems in class, using the full periodic table was very helpful. Throughout the unit, I continued to use this sheet to determine the charges of each of the problems and understand how elements around them relate to each other by charges.
When you are dealing with theses transition elements, you have to know how to label which charge
you are using for the specific ionic compound. You label the change depending on the amount of charge is being applied to the element. The amount of charge is shown with a roman numeral. Here is a chart from one of the worksheets were were completing about naming ionic compounds with multiple ions. After understand the topic that roman numerals determine the charge of the atoms, naming the compounds and finding the correct calculations for the compound is very simple task to handle.
Covalent or Molecular compounds- A combination of elements that are only nonmetals. Theses compounds require a prefix in front of the second element name. If you have 3 elements of the second element, "tri" will go infant of the name of the second element name. If there is only one element in the first element listed, the it doesn't start with "mono", but if the second element only has one element, then "mono" goes in front of the second element name. In my opinion, the most important thing to know about using prefixes is they only apply for molecular/covalent compounds. Here is the list of prefixes.
Going off of each of theses topics, another study we have learned is how to determine how many atoms and how many ions are in an element compound. In some of the problems, we are given the element name only and we have to determine the elements used and the formula to determine the amount of ions and atoms in the compound. When you are determining atoms, we look at the total amount of elements used in the compound equation. When you are determining the amount of ions, we determine the amount of single elements. Here are a few examples of problems when we use the study of the previous topics to find the amount of atoms and ions.
Finally, the last thing we did this week was the review guide. A few important concepts that we will need to know for the test is what happens to the conductivity through solids and liquids. On question 6 of the review guide, it asks us why sugar doesn't conduct electricity but salt does. Salt conducts electricity because the ionic combination of NaCl has a metal (Na or sodium). Due to the fact we know all metals conduct electricity, we know salt does. The covalent compound of C12H22O11 doesn't conduct electrify because it doesn't have ions so it is a neutral compound which doesn't conduct electricity. In addition, if sugar or salt was in a liquid, it would never conduct because electrons never go through water. Atoms need to be added and subtracted to cause some type of reaction and water is a neutral so that is not possible.
Other Notes to Remember From the Review Guide
- Chloride ions are non-metal and have more electrons than protons which makes it negative. Therefore, it has a negative charge.
- Postive ions have fewer electrons than neutral atoms, negative ions have more electrons than neutral atoms.
- We use the term formula unit instead of molecule because the formulas unit is the smallest whole number ration of a charge that gives you a neutral.
- Molecules apply to non-ions
- Molecules cannot be ions or have an ionic bond
- CO2 has a covalent bond because they are both non-metals
- SnO2 has an ionic bond because tin (Sn) is a metal.
- Going back to the Sticky-Tape lab, the pieces of tape will not exert a force when they are stuck together because they will have the same amount of change and same amount of atoms.
- Remember the top tape is positive and when they are separated, the top tape only has 2 atoms in each circle an the bottom tape is negatively charged with 4 atoms in each circle.
