ionic, metallic and covalent bonding writing and naming formulas
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the attraction between the positive nucleus of one atom and the negative electrons of another atom
Chemical bonds are formed by:
or by the attraction between positive and negative ions
Valence electrons
found in outermost energy level
electrons available to be lost, gained, or shared in the formation of chemical compounds
Octet Rule
Atoms tend to gain, lose, or share electrons in order to acquire a full set of eight valence electrons; stable noble gas configuration.
Three types of bonds:1. Ionic transfer of electrons between metal and nonmetal (or polyatomic ion)2. Metallic electron sea model; atoms of same metal 3. Covalent – sharing of electrons between nonmetals; may be same or different elements
atom, or a bonded group of atoms, that has a positive or negative charge
Ion
Ionic bond
electrostatic force that holds oppositely charged particles together
Write an electron configuration for sodium.
Write an electron configuration for neon.
What is the only difference in the electron configurations of these two elements?
Metals tend to lose electrons to form positive ions called cations.
Metals lose all valence electrons so that next energy level is full.
Predict if each would lose or gain electrons when forming compounds:
MagnesiumAluminumLithiumBariumPotassiumGallium
What cations would the following elements form? Write symbol and charge.
MagnesiumAluminumLithiumBariumPotassiumGallium
Use group number to predict charge of metal ion for representative elements only.
Group 1 1+
Group 2 2+
Group 13 3+
Transition metals
d block; filling inner energy levels
sometimes inner electrons take part in bonding
most form more than one common ion
Write an electron configuration for chlorine.
Write an electron configuration for argon.
What is the only difference in the electron configurations of these two elements?
Nonmetals tend to gain electrons to form negative ions called anions.
Nonmetals gain enough electrons to obtain full octet (8).
Predict if each would lose or gain electrons when forming compounds:
SulfurNitrogenIodinePhosphorusFluorineOxygen
What anions would the following elements form?Write symbol and charge.
SulfurNitrogenIodinePhosphorusFluorineOxygen
Writing formulas for binary ionic compounds:
1. Write symbol and charge for cation and anion.
2. Use subscripts to show the ratio of ions.
Ex: lithium and oxygen
Write formulas for the binary ionic compoundsformed between thefollowing elements:
a. potassium and iodine
b. magnesium and chlorine
c. sodium and sulfur
d. aluminum and nitrogen
e. aluminum and sulfur
Naming binary ionic compounds:
cation (metal) name of element; always written first
anion (nonmetal) name of element with an ‘ide’ ending
Name the binary ionic compounds indicated by the following formulas:
a. AgClb. ZnOc. CaBr2
d. SrF2
e. BaOf. CaCl2
Transition metals – d electrons can take part in bonding
How form multiple ions?
Write noble gas notation for tin:
[Kr] 5s24d105p2
Sn2+ or Sn4+
Fe2+ Cl-
iron(II) chloride
Fe3+ Cl-
iron(III) chloride
The charge on the metal is written as a Roman numeral in the name of compound.
FeCl2
FeCl3
Write the formula and name for the compounds formedbetween the following ions(use Roman numerals):
a. Cu2+ and Br -
b. Fe2+ and O2-
c. Pb2+ and Cl-
d. Hg2+ and S2-
e. Sn2+ and F-
f. Fe3+ and O2-
Writing names with Romannumerals:
1. Determine total negative charge.
2. Total negative charge equals total positive charge.
3. Charge on one positive ion is Roman numeral.
Ionic compounds containingpolyatomic ions:
Write formulas as you would for binary ionic compounds;use parentheses if adding subscript to polyatomic ion.
Write formulas for the following ionic compounds:
a. lithium nitrateb. copper(II) sulfatec. sodium carbonated. calcium nitritee. potassium perchlorate
Three types of bonds:1. Ionic transfer of electrons between metal and nonmetal (or polyatomic ion)2. Metallic electron sea model; atoms of same metal 3. Covalent – sharing of electrons between nonmetals; may be same or different elements
Why do atoms bond?
to obtain a full outer energy level; complete octet
to become more stable; lower potential energy
Electronegativity (EN)
indicates relative ability of an atom to attract electrons in a chemical bond
Covalent bond
chemical bond that results from the sharing of valence electrons
generally formed between two nonmetals (same or different element)
electrons are attracted by the nuclei of two different atoms
Naming binary molecular compounds
1. First element; use entire element name.
2. Second element ends in –ide.
3. Prefixes are used to indicate the number of atoms of each element – the subscripts.
Write formulas for thefollowing compounds:
a. carbon dioxideb. dinitrogen pentoxidec. silicon tetrafluoride
Ionic compounds
composed of large numbers of cations and anions; crystal lattice
formula unit – smallest whole number ratio of ions
Molecular compounds
composed of discrete (individual) molecules of covalently bonded atoms
molecular formulas do not need to be lowest ratio of atoms
a substance that produces hydrogen ions (H+) when dissolved in water
Acid
molecular compound that reacts with water to form ions
1. binary acid – two elements; hydrogen and a nonmetal
name begins with prefix‘hydro’ and ends with ‘ic’
HCl hydrochloric acid
2. oxyacid – hydrogen, oxygen, and a nonmetal; many formed from polyatomic ions
if name of polyatomic ion ends with ‘ate’ , name of acid ends with ‘ic’
H2SO4 sulfuric acid
Writing formulas for acids:
start with H+
determine charge on nonmetal ion or polyatomic ion
add subscripts if needed to make neutral compound
Electronegativity (EN)
indicates the relative ability of an atom to attract electrons in a chemical bond
Type of bond formed between two atoms depends on the difference in electronegativities (EN) of the atoms.
Difference in electronegativity (EN)
locate elements on periodic table
subtract values for EN
EN always positive
Polar covalent bond
unequal sharing of electrons
one atom pulling electrons towards itself
Covalent bonds may be:
atom with higher EN value has a partial negative charge ()
atom with lower EN value has a partial positive charge ()
Classify the following bonds as nonpolar- covalent, polar-covalent, or ionic. If bond is polar-covalent, assign partial charges.
C and H
H and Br
Cs and S
ions arranged in a regular repeating pattern called crystal lattice
Properties of ionic compounds
ions held together by strongionic bonds
Properties of ionic compounds
high melting and boiling points; much energy needed to separate ions
hard, rigid, brittle solids
aqueous solutions and liquid states are electrolytes - conduct electricity since ions are free to move
Properties of molecularcompounds
covalent bonds between atoms are strong, but attraction forces between molecules are weak
relatively weak forces of attraction between molecules
Intermolecular forces
also known as van der Waals forces
Properties of molecular compounds
relatively low melting and boiling points; many gases or liquids at room temperature
Properties of molecular compounds
do not conduct electricity when dissolved in water; except for acids
Metallic bond
outer energy levels of metal atoms overlap
valence electrons are shared by several atoms; delocalized (free to move)
electron sea model
Properties of metals
Properties of metals
moderately high melting points and high boiling points; most solids are room temperature
the more delocalized electrons a metal has, the greater its strength and hardness; groups 1 & 2 soft
good conductors of heat and electricity; electrons mobile
delocalized electrons interact with light, giving metals luster (shiny)
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