Chemistry Test

How does a covalent bond differ from an ionic bond?

In a covalent bond, atoms share one or more pairs of electrons. In an ionic bond, one atom transfers electrons to another.

Explain why the stability in item two does or does not hold true for most covalent bonds

Molecules are stable when they achieve a noble gas configuration with an outer shell of 8 electrons. Hydrogen is the exception to this rule since it achieves a noble gas configuration when it has two electrons in its outer shell.

predict wheter the binds between the following pairs of elements ar eionic polar or non polar Na-F H-I Al-O N-O S-O H-H

Na-F: ionic H-I: polar Al-O: ionic N-O: polar S-O: polar H-H: non-polar

name the following covalent bonds SF4 XeF4 PBr5 N2O5 Si3N4

SF4:sulfur tetraflouride XeF4:xenon tetrafloride PBr5:phosphate pentabromide N2O5:dinitride pentaoxide Si3N4: trisilicone tetranitride

Why is the H2 molecule more stable than two separate hydrogen atoms?

The H2 molecule is stable because each hydrogen atom now has a shared pair of electrons and has achieved a stable noble gas configuration.

Polar

Type of bond where a pair of electrons is unequally shared between two atoms

Non polar

Type of bond where two atoms share a pair of electrons with each other

covalent bond

a chemical bond in which atoms share a pair of valence electrons

noble gases

a group of chemical elements that do not readily form chemical bonds

molecule

a group of two or more atoms joined by chemical bonds

diatomic bond

a molecule that consisting of two atoms

shell

a particular region where electrons can orbit the nucleus of an atom

octet rule

a rue of thumb that states that atoms are most stable when surrounded by eight valence electrons

describe the differecces between a shared and an unshared pair of electrons ?

a shared pair is two electrons that are involved in forming a bind. an unshared pair is two electrons that are not envolved in forming a bond

valence electron

an electron in the outermost shell of an atom

nonmetal

an element that do not readily form chemical bonds

how does a covalent bond differ form an ionic bond?

covalent bonds- formed when atoms share one or more electrons ionic bonds- formed when an atom transfers electrons to another atom

a covalent bond in which two atoms share two pairs of electrons

double bond

how does one unbonded pair of electrons affect the shape of a molecule?

electrons in unbonded pairs push away bonded pairs as much as they possibly can

a structure in which atomic symbols represent nuclei and inner-shell electrons and in which dots are used to represent valence electrons

lewis dot structure

a possible Lewis structure of a molecule for which more than one Lewis structure can be written

resonance structure

a bond in which two atoms share one pair of electrons

single bond

what term is used to describe the situation when two or more lewis structures represent a molecule?

some molecules are represented by two or more lewis strutures that are called resonance structures. the molecule is a resonance hybrid of the two structures

valence

the number of chemical bonds an element is capable of forming

what does VSEPR theory predict?

the shape of a molecule based on its lewis dot structure

how is the VESPR theory useful?

the theory helps predict molecule shapes

a covalent bond in which two atoms share three pairs of electrons

triple bond

a nonbonding pair of electrons in the valence shell of an atom

unshared pair

an electron in the outermost energy level of an atom that can participate in bonding

valence electron

How does a covalent bond form between two atoms?

A covalent bond forms when two or more valence electrons are attracted by the positively charged nuclei of two atoms and thus are shared between both atoms.