2.  loss of valence electrons

4.  gain of negatively charged electrons  name of the anion typically ends in -ide

5.  Anion that gains 2 electrons

7.  compounds composed of cations and anions  electrically neutral  Held together by IONIC BOND › electrostatic forces

9.  Chemical Formula › indicates the number of atoms of each element found in each molecule of that compound  Formula Unit = lowest whole-number ratio of ions in an ionic compound › Ionic compounds do not exist as individual molecules

10.  All the electrons must be accounted for, and each atom will have a noble gas configuration (which is stable). CaP Lets do an example by combining calcium and phosphorus:

11. CaP

12. Ca 2+ P

13. Ionic Bonding Ca 2+ P Ca

14. Ionic Bonding Ca 2+ P 3- Ca

15. Ionic Bonding Ca 2+ P 3- Ca P

16. Ionic Bonding Ca 2+ P 3- Ca 2+ P

17. Ionic Bonding Ca 2+ P 3- Ca 2+ P Ca

18. Ionic Bonding Ca 2+ P 3- Ca 2+ P Ca

19. Ionic Bonding Ca 2+ P 3- Ca 2+ P 3- Ca 2+

20. Ionic Bonding = Ca 3 P 2 Formula Unit the smallest representative particle

21.  crystalline solids at room temperature  arranged in repeating three-dimensional patterns  very stable structure  high melting points

23.  Ionic compounds conduct electric current when melted or dissolved in water

24.  a neutral group of atoms joined together by covalent bonds  there is no such thing as a molecule of sodium chloride or magnesium chloride  ionic compounds exist as collections of positively and negatively charged ions

26.  Molecular compounds have relatively lower melting and boiling points than ionic compounds › gases or liquids at room temperature

27.  shows how many atoms of each element a molecule contains › water molecule = two hydrogen atoms and one oxygen atom  molecular formula = H 2 O. › carbon dioxide molecule = two oxygen atoms and one carbon atom  molecular formula = CO 2  Note: › If there is only one atom, the subscript 1 is omitted

28.  The molecular formula for ethane is C 2 H 6 › one molecule of ethane contains two carbon atoms and six hydrogen atoms  reflects the actual number of atoms in each molecule › not necessarily lowest whole-number ratios

29.  electron sharing occurs so that atoms attain the electron configurations of noble gases  likely to form covalent bonds: › atoms of the nonmetals and metalloids › Groups 4A, 5A, 6A, and 7A

30.  Two atoms held together by sharing a pair of electrons

31. pair of valence electrons not shared between atoms is called an unshared pair

35.  two shared pairs of electrons = double covalent bond  sharing three pairs of electrons = triple covalent bond.

37.  tightly bound group of atoms that has a positive or negative charge and behaves as a unit

38.  The negative charge of a polyatomic ion shows the number of electrons in addition to the valence electrons of the atoms present