Chem Exam 2

valence electrons

electron in the outermost electron shell of a representative element.

valence electrons in an atom of k?

1

valence electrons in an atom of Mg?

2

valence electrons in an atom of B?

3

valence electrons in an atom of C?

4

valence electrons in an atom of P?

5

valence electrons in an atom of S?

6

valence electrons in an atom of Br?

7

What do you use to find the umber of valence electrons?

group number

Lewis structure for k

Lewis structure for Mg

lewis sturcture for B?

octet rule

that atoms tend to gain, lose or share electrons until they have obtained the electron configuration of the nearest noble gas.

ion

atom (or group of atoms) that is electrically charged as a result of the loss or gain of electrons

anion

negatively charged ion

cation

positively charged ion.

how are positive ions formed?

atom loses a valence electron to achieve stable electron configuration

how are negative ions formed?

atoms gains a valnece electron to achieve a stable electron confifuration

when forming an ion, what charge is expected from Na (or any alkali metals)?

+1 (lose 1 electron)

when forming an ion, what charge is expected from Ca (or any alkaline earth metals)?

+2 (lose 2 electrons)

when forming an ion, what charge is expected from Al (or group 13)?

+3

when forming an ion, what charge is expected from N (or group 15)?

-3 (gains 3 electrons)

when forming an ion, what charge is expected from O (or group 16)?

-2

when forming an ion, what charge is expected from Cl (or group 17)?

-1

when forming an ion, what charge is expected from a noble gas?

0, stable

how many electrons are in F-?

10 (atomic number: 9 + 1 electron=10)

how many electrons are in Na?

11 (atomic number: 11 - 0)

how many electrons are in O2-?

10 (atomic number: 8 + 2 electons)

how many electrons are in Cl?

17 (atomic number: 17-0)

how many electrons are in K+?

18 (atomic number: 19 - 1 electron)

isoelectric species

atom and one or more ions that have identical electron configurations.

what elements are isoelectronic to argon?

Ar=18 electrons

S2-=16+2=18

K+=19-1=18

Cl-=17+1=18

Ca2+=20-2=18

predicted ratio formula of Al annd S

2:3

predicted ratio formula of Al annd Cl

1:3

predicted ratio formula of Ca annd O

1:1

predicted ratio formula of Na and N

3:1

predicted ratio formula of K annd S

2:1

what is each ion surrounded by?

ions of opposite charges

what are ions held together by?

electrostatic attractions

cooridnation number in sturcture of ionic compounds

Each cation is surrounded by a fixed number of anions, and each anion is surrounded by a fixed number of cations to maximize attraction and minimize repulsions between like charges.

what does the chemical formula represent?

simplest whole-number ratio of ions in the lattice, not an individual molecule.

Do ionic bonds have high or low melting and boiling points?

high melting and boiling points because breaking these strong lattice forces requires a lot of energy

do ionic solid conduct electricity?

yes

name of Na+ and Cl-

sodium chloride

name of Mg2+ (fixed charged cation)

magnesium ion

rule for naming binary ionic compound

Written first is the full name of the metal cation name followed by the name of the anion (stem + ide)

name of MgO

Magnesium oxide

name of Al2S3

Aluminum sulfide

metal with fixed charges

alkali metals, alkaline eart metals, aluminum, silver, zinc, scandium

metals with varying charges

most transition metals (iorn, copper, cobalt, nickel, chromium, manganses) and post transition metals (tin and lead)

different Cu names

I and II

different Fe names

II and III

different Co names

II and III

different Ni names

II and III

different Cr names

II, III, VI

different Mn names

II, III, IV, VII (2,3,4,7)

different Hg names

II and IV

different Sn names

II and IV

different Pb names

II and IV

different Au names

I and III

different Ti names

III and IV

different Bi names

III and V

how is something an ionic compound?

(# of cation*charge of cation)+(number of anion*charge of anions)=0

Name NaCl

sodium chloride

name MgSO4

magnesium sulfate

name AlBr3

aluminum bromide

name AgNO3

silver nitrate

name ZnO

Zinc Oxide

name CoCl2

cobalt II chloride

name CuBr

copper I bromide

name Fe(OH)3

Iron III hydroxide

name Fe2O3

Iron III oxide

Atoms in a polyatomic ion are connected by __________ bonds.

covalent

polyatomic ions

group of two or more covalently bonded atoms that carries an overall positive or negative electrical charge.

There are much ___ positive polyatomic ions than negative polyatomic ions.

less

number of atoms in aluminum carbonate

Al3+ CO2-3=Al2(CO3)3, 2 + 3 + 9 = 14

difference in ionic and covalent bond

ionic: transfer electrons, metal with nonmetal, 3D crystal molecule, high melting/boiling point, conducts electricity, generally solids

Covalent: sharing electrons, 2 nonmetals, individual molecules, lower melting/boiling point, poor conductors, gases/liquids/soft solids

examples of both ionic and covalent bonds

polyatomic ions (sodium nitraye, calcum carbonate, ammonium chloride)

bonding valence electrons

electrons shared between two atoms to form covalent bonds

nonbonding valence electrons

valence electrons that remain localized on a single atom and are not shared in chemical bonds.

how many nonbonding electron pairs in N2?

2

how many nonbonding electron pairs in CO2

4

how many nonbonding electron pairs in NH3

1

how many nonbonding electron pairs in CO2-3

8

how many nonbonding electron pairs in CH4

0

What is a coordinate covalent bond?

One atom (the donor or Lewis base) donates a lone pair of electrons, while the other atom (the acceptor or Lewis acid) provides an empty orbital to accept them

step 1 for molecular geometry of a molecule

draw lewis stucture

step 2 for molecular geometry of a molecule

count electron domains on central atom

step 3 for molecular geometry of a molecule

determine the electron geomtry by the number of domains (2-linear, 3- triagnular planar, 4-tetrahedral, 5-trignal bipyramidal)

step 4 for molecular geometry of a molecule

classify central atom, number of bonded atoms, and number of lone pairs on central atoms

steps for find formula for NH3

1. Central: N, 3 single bond to H and 1 lone pair on N

2. domains: 3 bonds+ 1 lone pair = 4 total domains

3. 3. tetrahedral

4. AX3E1

5. Molecular Geometry: trigonal pyramidal

step 5 for molecular geometry of a molecule

identify molecular geometry

single bond

1 electron group

double/triple bond

1 electron group

nonbonding electron pair

1 electron group

what is the electron group arragement for 2 electron groups?

linear

what is the electron group arragement for 3 electron groups?

trigonal planar

what is the electron group arragement for 4 electron groups?

tetrahedral

what is the electron group arragement for 5 electron groups?

trigonal bipyramid

what is the electron group arragement for 6 electron groups?

octahedral