II. Periodic Table J Deutsch 2003 2 The placement or location of elements on the Periodic Table...

II. Periodic Table

J Deutsch 2003 2

The placement or location of elements on the Periodic Table gives an indication of physical and chemical properties of that element. The elements on the Periodic Table are arranged in order of increasing atomic number. (3.1y)Mendeleev’s original table was according to mass. This was changed when Moseley discovered atomic number.

J Deutsch 2003 3

The number of protons in an atom (atomic number) identifies the element. 6C The sum of the protons and neutrons in an atom (mass number) identifies an isotope. Common notations that represent isotopes include: 14C, carbon-14, C-14. (3.1g)

Atomic number is written

on the bottom left.

Mass number is written on

the upper left.

J Deutsch 2003 4

Regents Question: 01/03 #9

An atom of carbon-12 and an atom of carbon-14 differ in

(1) Atomic number

(2) Atomic mass

(3) Nuclear charge

(4) Number of electrons

J Deutsch 2003 5


All the isotopes of a given atom have

(1) the same mass number and same atomic number

(2) the same mass number but different atomic numbers

(3) different mass numbers but the same atomic number

(4) different mass numbers and different atomic number

J Deutsch 2003 6


Atoms of the same element that have different numbers of neutrons are classified as

(1) Charged atoms

(2) Charged nuclei

(3) Isomers

(4) Isotopes

J Deutsch 2003 7

The average atomic mass of an element is the weighted average of the masses of its naturally occurring isotopes. (3.1n)Isotope Mass Abundance Calculation12C 12 98.89% 12 x .9889 = 11.87

13C 13 1.108% 13 x 0.01108 = 0.1440

Atomic Mass (weighted average)

12.01 amu

J Deutsch 2003 8

Atomic mass is found on the Periodic Table of the Elements

J Deutsch 2003 9


Hydrogen has three isotopes with mass numbers of 1, 2, and 3 and has an average atomic mass of 1.00794 amu. This information indicates that

(1) Equal number of each isotope are present

(2) More isotopes have an atomic mass of 2 or 3 than 1

(3) More isotopes have an atomic mass of 1 rather than 2 of 3

(4) Isotopes have only an atomic mass of 1

J Deutsch 2003 10


In which list are the elements arranged in order of increasing atomic mass?

(1) Cl, K, Ar

(2) Fe, Co, Ni

(3) Te, I Xe

(4) Ne, F, Na

J Deutsch 2003 11

Elements can be classified by their properties and located on the Periodic Table as metals, nonmetals, metalloids or semimetals (B, Si, Ge, As, Sb, Te), and noble gases. (3.1v)Metals on the left

Nonmetals on the rightMetalloids or semimetals

J Deutsch 2003 12

Regents Question: 01/03 # 37

Which list of elements contains two metalloids?

(1) Si, Ge, Po, Pb

(2) As, Bi, Br, Kr

(3) Si, P, S, Cl

(4) Po, Sb, I, Xe

J Deutsch 2003 13

Elements can be differentiated by their physical properties. Physical properties of substances, such as density, conductivity, malleability, solubility, and hardness, differ among elements. (3.1w)A physical property is one which does not change the identity of the substance when tested.

Density=mass/volume

J Deutsch 2003 14

All elements are solid at room temperature except for the following:

Liquids Mercury (Hg) - the only

liquid metal at room temperature

Bromine (Br) - the only liquid nonmetal at room temperature

Gases Hydrogen (H) Oxygen (O) Nitrogen (N) Fluorine (F) Chlorine (Cl) All of group 18 (noble gases)

Helium (He), Neon (Ne) Argon (Ar), Krypton (Kr), Xenon (Xe), Radon (Rn)

J Deutsch 2003 15

Comparing the physical properties of metals and nonmetals

Silvery gray color except copper and gold

Solid at room temperature except mercury

Good conductors of heat and electricity

Malleable – can be hammered into shapes (thin sheets)

Ductile – can be pulled into wires

Many different colors– Sulfur – yellow

– Chlorine – green

– Bromine – orange

– Iodine - purple

Many different states (phases)– H, N, O – gas

– Br – liquid

– S, C, I – solid

Poor conductors of heat and electricity (except carbon)

Brittle – breaks when hit

MetalsMetals Nonmetals

J Deutsch 2003 16

Regents Question: 06/03 # 6

Which is a property of most nonmetallic solids?

(1) high thermal conductivity

(2) high electrical conductivity

(3) brittleness

(4) malleability

J Deutsch 2003 17

Elements can be differentiated by chemical properties. Chemical properties describe how an element behaves during a chemical reaction. (3.1x)When testing a chemical property, the substance may

change into another substance.

The number of atoms an element combines with is an important chemical property:

NaCl CaCl2 AlCl3 CCl4

HCl H2O NH3 CH4

J Deutsch 2003 18

Some elements exist in two or more forms in the same phase. These forms differ in their molecular or crystal structure, and hence in their properties. (5.2f) These are called allotropes.Allotropes of oxygen Allotropes of carbon

Oxygen ( O2 ) Graphite

Ozone ( O3 ) Diamond

Buckminsterfullerene

J Deutsch 2003 19

For Groups 1, 2, and 13-18 on the Periodic Table, elements within the same group have the same number of valence electrons (helium is an exception) and therefore similar chemical properties. (3.1z)

J Deutsch 2003 20

Regents Question: 06/03 # 53-54

Given: Samples of Na, Ar, As, Rb

Which two of the given elements have the most similar chemical properties?

Explain your answer in terms of the Periodic Table of the Elements.

Na and Rb

They are in the same group

J Deutsch 2003 21

Group numbers and family names Group 1 Alkali Metals

– Very reactive metals, always found as compounds in nature

– 1 valence electron - lose 1 electron to form +1 ions

Group 2 Alkaline Earth Metals– Reactive metals, always found as compounds in nature

– 2 valence electrons - lose 2 electron to form +2 ions

Group 17 Halogens– Reactive nonmetals

– 7 valence electrons - gain 1 electron to form –1 ions

Groups 18 Noble Gases– Not reactive – do not form ions

– Filled, stable valence shell (8 electrons except He which has 2)

J Deutsch 2003 22


Which Group of the periodic Table contains atoms with a stable outer electron configuration?

(1) 1

(2) 8

(3) 16

(4) 18

J Deutsch 2003 23


Which element is classified as a noble gas at STP?

(1) Hydrogen

(2) Oxygen

(3) Neon

(4) Nitrogen

STP is standard temperature and pressure

0ºC (273K) and 1 atm (101.3kPa)

J Deutsch 2003 24

The succession of elements within the same group demonstrates characteristic trends: differences in atomic radius, ionic radius, electronegativity, first ionization energy, metallic/nonmetallic properties. (3.1aa)Going down a group, there are more shells separating the nucleus from the valence electrons

J Deutsch 2003 25

The succession of elements across the same period demonstrates characteristic trends: differences in atomic radius, ionic radius, electronegativity, first ionization energy, metallic/nonmetallic properties. (3.1bb)Going across a period, there are more protons pulling on the valence electrons

J Deutsch 2003 26

Reference Table S

J Deutsch 2003 27

Trends in Atomic Radius Atomic Radius – half the distance between

two nuclei Going down a group, the atomic radius

increases because there are more principal energy levels (shells)

Going across a period, the atomic radius decreases because there are more protons pulling the valence shell closer

J Deutsch 2003 28

Atomic Radius

J Deutsch 2003 29


Which list of elements is arranged in order of

increasing atomic radii?

(1)Li, Be, B, C

(2) Sr, Ca, Mg, Be

(3) Sc, Ti, V, Cr

(4) F, Cl, Br, I

Check Table S

J Deutsch 2003 30

Forming Ions – making atoms happy Atoms gain or lose electrons to complete their

outer shell– A noble gas configuration

– A complete octet

– 8 electrons

Metals lose electrons to form positive (+) ions Nonmetals gain electrons to form negative (-) ions Ionic Radius

– A negative ion is always larger than its original atom.

– A positive ion is always smaller than its original atom.

J Deutsch 2003 31


What is the total number of electrons in a Cu + ion?

(1) 28

(2) 29

(3) 30

(4) 36

J Deutsch 2003 32

Ionic Radius in Metals Sodium (Na) is a metal

– Electron configuration 2-8-1• (11 protons and 11 electrons)

– Loses 1 electron in its valence shell– A sodium atom becomes a sodium ion

• Na+

• 2-8 (10 electrons but 11 protons)

– Same electron configuration as a noble gas (Ne) but has more protons. Electrons are pulled in much closer so the radius decreases.

2+ ions are even smaller than + ions

J Deutsch 2003 33

Ionic Radius in Nonmetals Chlorine (Cl) is a nonmetal

– Electron configuration 2-8-7• (17 protons and 17 electrons)

– Gains 1 electron in its valence shell– A chlorine atom becomes a chloride ion

• Cl-

• 2-8-8 (18 electrons but only 17 protons)

– Same electron configuration as a noble gas (Ar) but has fewer protons. Electrons repel each other and the radius increases.

2- ions are even larger than – ions

Notice-name of negative ions end in IDE

J Deutsch 2003 34


As a neutral sulfur atom gains two electrons, what happens to the radius of the atom?

It gets bigger

J Deutsch 2003 35


After a neutral sulfur atom gains two electrons, what is the resulting charge of the ion?

2-

J Deutsch 2003 36


Which electron configuration is correct for a

sodium ion?

(1) 2–7

(2) 2–8

(3) 2–8–1

(4) 2–8–2

J Deutsch 2003 37


Which ion has the same electron configuration as an atom of He?

(1) H–

(2) O2–

(3) Na+

(4) Ca2+

- means gains 1 electron

2- means gains 2 electrons

+ means loses 1 electron

2+ means loses 2 electrons

GIN LIP

Gaining electrons makes Ions Negative

Losing electrons makes Ions Positive

J Deutsch 2003 38


Which of the following ions has the smallest radius?

(1) F-

(2) Cl-

(3) K+

(4) Ca2+

J Deutsch 2003 39


As an atom becomes an ion, its mass number

(1) Decreases

(2) Increases

(3) Remains the sam

J Deutsch 2003 40


Compared to the radius of a chlorine atom, the radius of a chloride ion is

(1) Larger because chlorine loses an electron

(2) Larger because chlorine gains an electron

(3) Smaller because chlorine loses an electron

(4) Smaller because chlorine gains an electron

J Deutsch 2003 41

Trends in Electronegativity Electronegativity – the relative ability of an atom

to attract electrons (in a chemical bond) Fluorine (F) has the highest electronegativity and

is assigned the value 4.0 Francium (Fr) has the lowest electronegativity. Going down a group, electronegativity decreases

because there are more shells and the electron being attracted is far from the protons

Going across a period, electronegativity increases because there are more protons in the nucleus to attract the electrons. (same number of shells)

J Deutsch 2003 42


Which of the following atoms has the greatest tendency to attract electrons?

(1) Barium

(2) Beryllium

(3) Boron

(4) Bromine

J Deutsch 2003 43


The strength of an atom’s attraction for the electrons in a chemical bond is the atom’s

(1) Electronegativity

(2) Ionization energy

(3) Heat of reaction

(4) Heat of formation

J Deutsch 2003 44

Trends in First Ionization Energy First ionization energy is the amount of energy

needed to remove the most loosely held electron from an atom in the gaseous state.

Going down a group, first ionization energy decreases because there are more shells and the electron being attracted is far from the protons

Going across a period, first ionization energy increases because there are more protons in the nucleus to attract the electrons. (same number of shells)

J Deutsch 2003 45


From which of these atoms in the ground state can a valence electron be removed using the least amount of energy?

(1) Nitrogen

(2) Carbon

(3) Oxygen

(4) Chlorine

J Deutsch 2003 46

Trends in Metallic Properties Metals want to lose electrons to complete their

outer shells Metals form positive (+) ions Metals have low electronegativity Metals have low first ionization energy Metallic properties (characteristics) decrease as

you go to the right across a period Metallic properties increase as you go down a

group Going towards Francium (Fr), metallic properties

increases.Anything that increases an atom’s ability to lose electrons, increase the atoms metallic characteristics.

J Deutsch 2003 47

Trends in Nonmetallic Properties Nonmetals want to gain electrons to complete

their outer shells Nonmetals form negative (-) ions Nonmetals have high electronegativity Nonmetals have high first ionization energy Nonmetallic properties (characteristics) increase

as you go to the right across a period Nonmetallic properties decrease as you go down a

group Going towards Fluorine (F), nonmetallic

properties increases.Anything that increases an atom’s ability to gain electrons, increase the atoms nonmetallic characteristics.

J Deutsch 2003 48


Which of the following Group 15 elements has the greatest metallic character?

(1) Nitrogen

(2) Phosphorous

(3) Antimony

(4) Bismuth

J Deutsch 2003 49


Which are two properties of most nonmetals?

(1) High ionization energy and poor electrical conductivity

(2) High ionization energy and good electrical conductivity

(3) Low ionization energy and poor electrical conductivity

(4) Low ionization energy and good electrical conductivity

J Deutsch 2003 50

Regents Question: 06/02 #67-69

On the grid in your answer booklet, set up a scale for electronegativity on the y-axis. Plot the data by drawing the best-fit line.

Using the graph, predict the electronegativity of nitrogen

For these elements, state the trend in electronegativity in terms of atomic number.

Element Atomic Number Electronegativity

Beryllium 4 1.6

Boron 5 2

Carbon 6 2.6

Fluorine 9 4.0

Lithium 3 1.0

Oxygen 8 3.4

J Deutsch 2003 51

Regents Question: cont’d

J Deutsch 2003 52

Regents Question: cont’d

1

2

3

4

J Deutsch 2003 53

Regents Question: Cont’d

On the grid in your answer booklet, set up a scale for electronegativity on the y-axis. Plot the data by drawing the best-fit line.

Using the graph, predict the electronegativity of nitrogen

For these elements, state the trend in electronegativity in terms of atomic number. As the atomic number increases, the

electronegativity increases.

1

2

3

4

3.0

II. Periodic Table J Deutsch 2003 2 The placement or location of elements on the Periodic Table...

Documents

Transcript of II. Periodic Table J Deutsch 2003 2 The placement or location of elements on the Periodic Table...