Ionic compounds Flashcards
Describe the formation of ions by the gain or loss of electrons
Loss of an electron - Positively Charged Ions
Gain of an electron - Negatively Charged Ions
Group 1 - 3 will form CATIONS (Postive Ions)
Group 5 - 7 will form ANIONS (Negative Ions)
Group 0 & 8 are unreactive, therefore they do not form ions.
What is oxidation and reduction?
Oxidation is the loss of electrons and Reduction is the gain of electrons
Recall the charges of common ions in this specification
Hydrogencarbonate - HCO3- Carbonate - CO3 2- Sulpahte - So4 2- Sulphite - SO3 2- Suplide - S 2- Nitride - N 3- Phospahte - PO4 3-
Deduce the charge of an ion from the electronic configuration of the atom from which the ion is formed
Electronic configuration of ions
Na has the electronic configuration of 2,8,1
It’s positive ion, Na+, has the electronic configuration of 2,8. Na loses an electron to another atom, therefore becomes positive.
Cl has the electronic configuration of 2,8,7
It’s negative ions, Cl-, has the electronic configuration of 2,8,8. Cl gains an electron from another atom, therefore becomes negative.
Explain, using dot and cross diagrams, the formation of ionic compounds by electron transfer, limited to combinations of elements from Groups 1, 2, 3 and 5, 6, 7
An electronic transfer takes place. Na has one electron on it’s outer shell, therefore it wants to lose it to have a complete outer shell. Na gives one electron to Cl
Cl has seven electrons on it’s outer shell, therefore it wants to gain one electron to have a complete outer shell
Cl gains one electron from N. The Na atom becomes a positive ion by losing one electron. The Cl atom becomes a negative ion by gaining one electron
What is ionic bonding?
A strong electrostatic attraction between oppositely charged ions
What are the properties of ionic compounds?
Ionic compounds have high melting and boiling points because of strong electrostatic forces between oppositely charged ions
What is the relationship between ionic charge and the melting point and boiling point of an ionic compound?
The greater the charge, the stronger the bond as opposing forces are stronger. More difficult to break the bonds, melting and boiling points will be higher. The bigger the charge of an ion, the higher the melting and boiling point.
Describe an ionic crystal as a giant three-dimensional lattice structure held together by the attraction between oppositely charged ions
An ionic crystal is a lattice of electrons in a 3D structure, the ions are alternate positive and negative and their opposing charges hold the structure together.
