Unit 4 Flashcards
Ionic Bond
A type of chemical bond formed between two ions of opposite charges. One atom donates electrons, becoming positively charged (cation), while the other accepts electrons, becoming negatively charged (anion). The attraction between the oppositely charged ions holds them together.
Covalent Bond
A chemical bond formed by the sharing of electron pairs between two atoms. This sharing allows each atom to achieve a more stable electron configuration, typically resembling that of noble gases (having 8 valence electrons).
Electronegativity
A measure of an atom’s ability to attract and hold onto electrons in a chemical bond. Electronegativity increases right up on the periodic table.
Ionization energy
The amount of energy required to remove an electron from an atom or a positive ion
Molecule
a group of atoms bonded together covalently
Valence electron
Electrons located in the outermost energy level of an atom. The number of valence electrons determines the chemical properties and reactivity of an element.
Malleable
the ability for a metal or metal alloy to be formed into a variety of shapes. Malleable substances can be hammered or rolled into thin sheets.
Ductile
property of a metal that can be stretched into a thin wire
Sea of Electron Model
A model of a metallic bond, where the outermost electrons roam around each atom as they are not connected to an atom.
Crystal lattice structure
in an ionic solid, the ions are packed together into a repeating array called a crystal lattice
Properties of Ionic Compounds
-High melting points
-Hard and brittle
- dissociate into ions when dissolved in water
-melted ionic compounds conduct electricity (not as a solid)
Properties of covalent molecules
-low boiling/melting point
-Can be found in all three physical at room temperature
- they do not conduct electricity
Polar covalent bond
Atoms share electrons unequally when forming a bond. The more electronegative atom has a stronger attraction for the electrons
Nonpolar covalent bond
Atoms share electrons equally when forming a bond
Polar molecule
If the bond is polar and the shape is not symmetrical
A molecule has regions that are partially positive and partially negative
Nonpolar molecule
any nonpolar bond or symmetrical shape
A molecule does not have regions that are partially positive or negative
Dipole
a measurement of change separation from positive to negative
Net Dipole
A total dipole across the entire molecule
Intramolecular force
Forces within a compound that bond atom to atom together (ionic/covalent/metallic)
intermolecular force
forces that exist between molecules holding them together (something like glue)
London Dispersion Force (LDF)
In all molecules, the larger the molecule the stronger the force
Dipole-Dipole
-In all polar molecules
-The attractive force between molecules due to the existence of an overall dipole moment
Hydrogen Bond
in all polar molecules that have a hydrogen bonded with a N,O or F
