Honors Chemistry Q2 Test - Combine Q1 and Q2

Across a Period Properties

D

I

I

D

I

Down a Group Properties

I

D

D

I

D

Explaining the Periodic Trends for Down a Group

more electron shells

Explaining the Periodic Trends Across a Period

more proton pull

When there is a small nuclear charge, generally, how big is the radius?

Larger

How to find what ions are smaller or larger

• Larger radii will be on ions that gain electrons

• Find how much proton pull there is

Dimitri Mendeleev

• Had elements arranged in order of increasing atom mass show similar chemical and physical properties

• This occurs at periodic intervals

• Modern Periodic Law: the physical and chemical properties of elements are periodic functions of their atomic numbers

Periods

Horizontal rows, the number of the period indicates the highest principal energy level with electrons(shells)

Groups(families)

vertical columns on periodic table

sum number of valence electrons means

similar properties

metals general definition

elements located to the left of the staircase(75% of the table)

metalloid general definition

elements adjacent to the staircase(excluding Al)

nonmetals general definition

elements located to the right of the staircase

common properties of metals

• solids at room temperature(excluding Hg)

• malleable

• ductile

• have luster

• good conductors of heat and electricity because of highly mobile valence electrons

• low ionization energy

• low electronegativity values

• need to lose electrons to form positive ions(cations) with smaller radii

Why do metals conduct electricity?

valence electrons in metals move freely throughout the structure

properties of nonmetals

• many are gases at room temperature(bromine is a liquid)

• some are network solid like diamond

• brittle

• solids are dull

• poor conductors of heat and electricity

• high ionization energy

• high electronegativity values

• tend to gain electrons to form negative ions(anions) with larger radii

Metalloids

• intermediate elements that display both metallic and nonmetallic properties

  • conduct electricity, but not as well as metals

  • shiny like metals but brittle like nonmetals

Noble Gases

• group 18

• unreactive

• have completely filled valence electrons shells

• stable electron configuration

• H & He = duet rule

Octet Rule

atoms will gain, lose, or share electrons in order to obtain a stable octet of electrons

Hydrogen

• doesn’t have properties similar to group 1(detached)

• nonmetal

• only element that can gain, lose, or share its one valence electrons to become stable

• can form a +1 or -1 ion

Group 1(alkali metals) and Group 2(alkaline earth metals)

• most reactive metals(group 1 > group 2, bottom of group > top of group)

• reactive metal means they easily lose their electrons

• can only be found in compounds in nature(free elements are produced by the electrolysis of the fused compounds)

Group 3-12: transition elements/metals

• outermost d sublevels are being filled(non valence electrons)

• typically hard solids with high melting points(except Hg)

• transition elements typically have multiple oxidation(ionic) states(e- lost from more than one energy level)

• less reactive than group 1 and group 2(copper, silver, gold are the least reactive)

• transition elements typically form colored ions in solution

Group 14(carbon group)

• structure = function

• nonmetals that typically form network solids

• carbon can have multiple forms in the same form(diamond vs. graphite)

allotropes

nonmetals that exist in two or more forms in the same phase. they have different chemical and physical properties because they have different structures(oxygen vs ozone and white vs red phosphorus)

Group 15 and Group 16

• nitrogen and oxygen are both diatomic

• BrINCl HOF

• nitrogen contains a triple bond

• oxygen contains a double bond

Group 17(halogens)

• in a compound they are called halides

• only group that contains all these phases of matter at room temperature

• most reactive of the nonmetals

• nonmetals react by gaining electrons

• the top of the group is more reactive than the bottom of the group

• can only be found in a combined state in nature(like group 1 and group 2)

Ion Formation for Groups

Group 1 - lose one electron, form a +1 ion

Group 2 - lose two electrons, form a +2 ion

Group 13 - lose three electrons, form a +3 ion

Group 16 - gain two electrons, form a -2 ion

Group 17 - gain one electron, form a -1 ion

number of e-s lost = number of e-s gained

atomic radius trend across a period

decreases

electronegativity trend across a period

increases

first ionization energy trend across a period

increases

metallic character(reactivity) trend across a period

decreases

nonmetallic character(reactivity) trend across a period

increases

atomic radius trend down a group

increases

electronegativity trend down a group

decreases

first ionization energy trend down a group

decreases

metallic character(reactivity) trend down a group

increases

nonmetallic character(reactivity) trend down a group

decreases

Why are periodic trends doing what they do down a group

more electron shells

Why are periodic trends doing what they do across a period?

more proton pull

how to find radius size

first, find what is positive and negative and sort accordingly

then, find the number of electrons

Most of the groups in the Periodic Table of the Elements contain

nonmetals and metals

Compared to atoms of metals, atoms of nonmetals generally

1. lose electrons more readily

2. have higher electronegativities

3. conduct electricity more readily

4. have lower first ionization energies

2. have higher electronegativities

A diatomic element with a high first ionization energy would most likely be a

1. nonmetal with a high electronegativity

2. metal with a high electronegativity

3. metal with a low electronegativity

4. nonmetal with a low electronegativity

1. nonmetal with a high electronegativity

The elements of the Periodic Table are arranged in horizontal rows according to each successive element’s greater

1. number of protons

2. number of neutrons

3. atomic radius

4. atomic mass

1. number of protons

When combining with nonmetallic atoms, metallic atoms generally will

1. lose electrons and form positive ions

2. gain electrons and form negative ions

3. gain electrons and form positive ions

4. lose electrons and form negative ions

1. lose electrons and form positive ions

Which metal atoms can form ionic bonds by losing electrons from both the outermost and next to outermost principal energy levels?

1. Ca

2. Pb

3. Fe

4. Mg

3. Fe

Compared to the halogens in period 3, the alkali metals in period 3 have

1. greater nuclear charge

2. fewer valence electrons

3. a higher electronegativity

4. a smaller atomic radius

2. fewer valence electrons

Which element is relatively inactive at room temperature?

1. oxygen

2. chlorine

3. nitrogen

4. fluorine

3. nitrogen

Which metals are produced commercially only by electrolysis of their fused salts?

1. Be and Fe

2. Sr and Cr

3. Na and Ca

4. Li and Ni

3. Na and Ca

Which formula contains an alkaline earth metal and a halogen?

1. NaCl

2. CaO

3. MgCl2

4. Na2O

3. MgCl2

Which of the following ions has the smallest radius?

1. K+

2. Mg2+

3. Ca2+

4. Na+

2. Mg2+

Which element in Period 3 has the greatest tendency to gain electrons?

1. Ar

2. Cl

3. Si

4. Na

2. Cl

Atoms of metallic elements tend to…

lose electrons and form positive ions

As we move down Group 1 elements of the Periodic Table, the first ionization energy of each element decreases. One reason for this is that

1. the nuclear charge is decreasing

2. the number of principal energy levels is decreasing

3. the distance between the valence electrons and the nucleus is increasing

4. the number of neutrons is increasing

3. the distance between the valence electrons and the nucleus is increasing

Which of the following generally applies to the noble gases?

1. high ionization energy, low electronegativity, high reactivity

2. high ionization energy, high electronegativity, high reactivity

3. low ionization energy, low electronegativity, low reactivity

4. high ionization energy, low electronegativity, low reactivity

3. low ionization energy, low electronegativity, low reactivity

The radius of a calcium ion is smaller than the radius of a calcium atom because the calcium ion contains the same nuclear charge and

1. fewer electrons

2. fewer protons

3. more protons

4. more electrons

1. fewer electrons

Metallic bonds have the…

highest melting and boiling point

Different properties mean…

different structures

Formation of Bonds

• atoms must form chemical bonds to become stable(octet rule)

• a chemical bond results from the simultaneous attraction of electrons to two or more nuclei(protons attract electrons)

• what elements and how the bond forms determine the structure and the properties of the compound

Energy and Bonds

• the formation of a chemical bond is exothermic(releases energy)

  • unstable→stable

• the breaking of a chemical bond is endothermic(absorbs energy)

  • takes energy to break a very stably bond

• the more energy released when a bond forms, the stronger the bond

Ionic bonds

are formed by a metal ion(cation) and a nonmetal(anion)

Covalent bonds

are formed by nonmetals overlapping their electron clouds(sharing electrons); also called molecular compounds

Metallic bonding

occurs when metal atoms delocalize their electrons to stabilize their structure

How ionic bonds form…

• an ionic bond is formed by the transfer of one or more electrons from a metal to a nonmetal

  • the greater the electronegativity difference, the more ionic character

• the transfer of electrons results in the formation of ions

• the opposite ions stick together and form an ionic bond

Structure of Ionic Compounds

• crystal lattice due to contributing attractions

• lattice is lower in energy and is strong which results in a higher melting and boiling point

Properties of Ionic Compounds

• ionic solids have high melting points/boiling points(strong forces holding the ions together), hard substances

• ionic solids don’t conduct electricity(ions are held in a fixed lattice)

• ionic liquids or aqueous solutions of ionic compounds will conduct electricity(dissolving separates the ions, allows them to move)

  • makes electrolytes

electrolytes

substance that conducts electricity when dissolved

How does metallic bonding work?

• metal atoms are arranged in a crystal lattice where the valence electrons move freely between all the atoms(delocalized and shells are gone)

• best thought of as a “sea of mobile electrons”(allow for good electrical conductivity

  • metallic bonding is a strong attraction causing the melting point and boiling point of metals to be high

How covalent bonding works?

• a covalent bond is formed when two or more nonmetals share electrons

• covalent bonds are used to form both molecular compounds and network solids(diamonds or quartz)

• nonmetals can form more than one bond(2 e- shared per bond)

• Lewis dot diagrams can predict these structures

Properties of Molecular Compounds

• made of individual molecules

• covalent bonds hold the atoms together to form a molecule(the H is covalently bonded to the O in H2O)

• molecules are attracted to each other by forces that are weaker than bonds(why melting point and boiling point are low)

• molecular compounds typically are soft, having low melting point and boiling point

• non-conductors in all phases(including H2O)

Structure of Network Solids

• same or different elements connected to each other by covalent bonds

• in a hard crystalline structure

• high melting and boiling points

• covalent bonds holding them together are not easily broken

terms for ionic solids

ions held by ionic bonds

terms for metallic solids

metal atoms held by metallic bonds

terms for molecular solids

molecules held by intermolecular forces

terms for network solids

atoms/molecules held by covalent bonds

in ionic, metallic, and network solids, ____ are the force holding the particles together

strong bonds

in a molecular solid, ____ are the glue holding it all together

weaker secondary forces

ionic liquids can…

conduct

The forces between atoms that create chemical bonds are the result of interactions between

protons and electrons

Lewis Electron Dot Diagram

pen and paper model that shows the electrons in an atom or a molecule

• essential for determining the structure of molecules

Steps for Lewis Electron Dot Diagram for A Single Element

1. write the symbol for the element

2. place a dot for each valence electrons around the atom

3. alternate sides when placing the electrons(clockwise)

What’s the max amount of valence electrons in an atom?

8

How many orbitals are there to fill with electrons in a Lewis Electron Dot Diagram?

4

Dot Diagrams for Covalent Compounds(Regents)

1. Arrange the atoms(fewest valence electrons = center atom) using single bonds

2. Add remaining electrons as dots(work outside in)

3. Check everyone’s octet, if everyone is stable, you’re done; also check atoms and total # of electrons

4. Not enough electrons in your diagram?

   1. add a double or triple bond and check again

if possible, follow bond order rules and use electron expulsion theory and hund’s rule

Covalent Bonding Tricks

1. Hydrogen only makes single bonds because of its duet, never goes in the middle, and has no lone pairs

2. Group 17 only makes single bonds and never goes in the middle(6 lone pairs of electrons)

3. Group 16 likes to make double bonds, but can make single

4. Group 15 likes to make triple bonds, but can make double and single

5. Carbon always goes in the middle if it’s there

6. Least electronegative element goes in the middle

Polyatomic Ions

an ion that contains more than one atom has net charge when the total group has either gained or lost an electron

How to Draw Diagrams for Polyatomic Ions

1. add charge in the upper right hand corner of the diagram

2. add extra electron to total if -, subtract if +

Ionic Compound Diagrams Rules

for cations:

• symbol and positive charge

• no dots(metals lose their valence electrons)

for anions:

• symbol and negative charge

• 8 dots(nonmetals gain enough electrons to complete the octet)

other:

• arrange the ions however you want

• no dashes between them

If there are multiple possible charges,

let the multiple molecules cancel out

Solubility

• like dissolves like = polar compounds dissolve polar compounds, nonpolar dissolves nonpolar

Intermolecular Forces

• related to the phase of matter and the MP/BP

Ions held together

ionic bonds

Metals atoms held together

metallic bonds

Network solids held together

covalent bonds

molecular solids held together

• intermolecular forces)weaker than bonds)

Dipole-Dipole Attraction

• made polar covalent molecules and happens when opposites attract

London Dispersion Forces

• made by nonpolar covalent molecules and happens electrons shift making temporary poles that attract, but are weak

Hydrogen Bonding

made by an H and N, O, F and happens when these molecules are covalent bonded making a large dipole, because the FON are highly electronegative