Unit B Section 3.2 Flashcards
What is an ionic compound?
Ionic compounds are pure substances formed as a result of the attraction between particles of opposite charges, called ions.
Properties of ionic compounds?
- Produced from metal and nonmetal
- High melting and boiling point
- Good conductivity
- solid at room temperature
- distinct crystal shape
- breaks into ions in solutions
When an ionic compound is melted or dissolved in water, it will conduct electricity. This property of ionic compounds led to the study of electrochemical cells (cells that either converts chemical energy into electrical energy or electrical energy into chemical energy).
When an ionic compound is dissolved in water…
the metal and nonmetal form an aqueous solution of ions.
superscript position?
To indicate ions in written notation, a plus sign (+) or a minus sign (-) is placed to the upper right of the element symbol.
Ex. Na+
polyatomic ions?
Polyatomic ions are a group of atoms acting like one. For example, one atom of carbon and three atoms of oxygen form the polyatomic ion called carbonate or
CO32-.
How to name ionic compounds?
1) the chemical name of the metal or positive ion goes first, followed by the name of the non-metal or negative ion.
2) the name of the non-metal negative ion changes its ending to ide.
One exception to these naming rules?
Where negative ions are polyatomic ions, the name remains unchanged. Limestone’s chemical
the name, therefore, remains calcium carbonate.
What happens when there is more than one ion charge
Some elements have this property. To show clearly
which ion is being used in a chemical name, a Roman numeral is added. For example, iron(II) oxide is a compound containing the Fe2+ ion.
How to write formulas for ionic compounds:
1) Print the metal element’s symbol with its ion charge. print the non-metal element’s symbol with its ion charge.
2)The positive ion charge must balance the negative ion charges. there must be two chlorine atoms each with an ion charge of 1 to balance the 2+ ion charge
of one calcium atom.
3)Write the formula by indicating how many atoms of each element are in it. Do not include the ion charge in the formula. Place the number of atoms of each element in a subscript after the element’s symbol. If there is only one atom, no number is used.
Ion charges in the Periodic table?
- The first group of elements on the left side of the table is the alkali group of metals—lithium and
sodium. They each have an ion charge of 1.
-The halogens, on the right of the table—fluorine and
chlorine—have an ion charge of 1.
-Generally, all the elements in a group form ions with the same charge. This pattern is the most consistent at either end of the periodic table. Figure 3.9 illustrates the ion charges of the elements that follow this pattern the best.