Chapter 9: Ionic Covalent Bonding Flashcards
What is a chemical bond?
A strong attractive force that exists between certain atoms in a substance.
Ionic bonding results from attractive force of oppositely charged ions.
What is a covalent bond?
Two atoms share valence electrons (outer-shell electrons), which are attracted to the positively charged cores of both atoms.
(Most atoms are linked by covalent bonds).
What is metallic bonding?
Seen in sodium and other metals, represents another important type of bonding. A crystal of sodium metal consists of a regular out the crystal, attracted to the positive cored of all Na+ Ions.
What are Ionic bonds?
A chemical bond formed by the electrostatic attraction between positive and negative ions.
The bond forms between two atoms when one or more electrons transferred from the valence shell of one atoms to another.
What occurs when atoms come together and bond?
There will be a net decrease in enegery because the bonded state should be more stable and therefore ata lower energy level.
What is Coulomb’s law?
Used to calculate the energy obtained when ion spheres come together.
States that the potential energy obtained in bringing two charges Q1 and Q2, initially far apart, up to a distance R apart is directly proportional to eh product of the charges and inversely proportional to the distance between them.
What is the lattice energy?
The change in energy that occurs when an ionic solid is separated into isolated ions in the gas phase.
In general, bonding between a metal and nonmetal is?
Ionic as reactive metal has low ionization energy and a reactive nonmetal has large electron affinity.
Properties of ionic substances?
- High melting points
What are the categories that monatomic ions found in compounds of the main-group elements fall into?
- Cations of groups IA to IIIA having noble-gas or pseudo-noble-gas configurations. The ion charges equal the group numbers.
- Cations of Groups IIIA to VA having ns2 electron configurations. the ion charges equal the group numbers minus two. Examples are Tl+, Sn2+, Pb 2+
- Anions of Groups VA to VIIA having noble-gas or pseudo-noble-gas-configurations. The ion charges equal the group numbers minus eight.
What is an ionic radius?
A measure of the size of spherical region around the nucleus of an ion within which the electrons are most likely to be found.
How do you define an ionic radius?
It is arbitrary because an electron distribution never abruptly ends.
Who proposed that the strong attractive force between two atoms in a molecule results froma. covalent bond?
Gilbert Newton Lewis (1916)
What is a polar covalent bond?
A bond in which the bonding electrons spend more time near ne atom than the other. EXP: HCl - the bonding electrons spend more time near chlorin than the hydrogen.
What are the least electronnegative elements?
Metals (they are electro-positive)
What are the two exceptions to the octet rule?
- A group of moleculres with an atom having fewer than eight valence electrons around it
- a group of molecules with an atom having more than eight valence electrons aroun it.
