Presentation on theme: " Electrons in the highest occupied energy level of an element’s atoms To find the number of valence electrons in an atom of a representative element,"— Presentation transcript:
Electrons in the highest occupied energy level of an element’s atoms To find the number of valence electrons in an atom of a representative element, simply look at its group number. If it’s in group 1 or 2. If it is in groups subtract 10 to find the number of valence electrons.
In the formation of compounds, atoms tend to achieve the electron configuration of a noble gas. Atoms either gain, lose, or share electrons to form compounds.
Loses an e- -An atom’s loss of valence electrons produces a cation, or a positively charged ion.
Metals – lose valence e- easily Transition metals – have 2 valence e-, usually lose those two to form 2+ ions, but can also lose d electrons to form other ions
Nonmetals easily gain e - to form negative ions to get to 8 valence e - Gains an e- Chloride ion
-Nonmetals usually gain e - Some can gain or lose, but will gain most often
- The lowest whole-number ratio of ions in an ionic compound.
When oppositely charged ions attract, electrostatic force that holds them together = ionic bond Compounds containing ionic bonds = ionic compounds Electrons are transferred from cations to anions Bonds formed between metals and nonmetals (or contain a polyatomic ion)
Most ionic compounds are crystalline solids at room temperature. Arranged in repeating three-dimensional patterns Ionic compounds generally have high melting points Large attractive forces result in very stable structures
Ionic compounds can conduct an electric current when melted or dissolved in water. When ionic compounds are dissolved in water the crystalline structure breaks down. This allows the ions to move freely which results in conductivity.
The positive Na ions move to the cathode and the negative Cl ions move to the anode.
Metals are good conductors because the valence electrons are able to flow freely within them. Valence electrons of metals can be thought of as a sea of electrons.
The ductility and malleability of metals can be explained by the mobility of electrons in metals. When a metal is subjected to pressure, the cations easily slide past each other like a ball bearing immersed in oil. If an ionic crystal is stuck with a hammer the cations are pushed together, repel, and the crystal shatters.