1 Electronegativity Which element has the highest value for The - - PDF document

SLIDE 1

1

• E it takes to remove an e- from a gaseous atom

producing a gaseous ion

• Measured in kJ/mole
• The relative ability of an atom to attract e-
• unitless

Periodic Trends of Atomic Properties

First Ionization Energy Electronegativity

• Always (+) value =

How does IE change within a period? M → M+

First Ionization Energy E +

requires E to strip e- from atom e- attracted to p+ + 1e- Metals- Nonmetals- IE ↑ from left to right:

+ +

• metal

nonmetal Two atoms in the same period: Easier to pull off e- More difficult to pull off e-

• Always (+) value =

How does IE change within a period? M → M+

First Ionization Energy E +

requires E to strip e- from atom + 1e- Metals- Nonmetals- large atom w/ few valence e- held less tightly by nuclear charge smaller atoms w/ valence e- held more tightly by nuclear charge low IE high IE IE ↑ from left to right:

1

H He

2

Li Be B C N O F Ne

3

Na Mg Al Si P S Cl Ar

4

K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr

5

Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe

6

Cs Ba Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn

7

Fr Ra Rf Ha Sg Ns Hs M t Uun

(6)

La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu

(7)

Ac Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr

How does IE change within a group? Li Na K Rb Cs Fr Further from nucleus, ___________________ Takes _______ to remove e- from 7s than 1s

Outermost

• rbital:

2s Small atom 7s Large atom 3s 4s 5s 6s

increase increases less E e- held more loosely

atomic atomic # # vs.

• vs. 1st IE

IE

5 10 15 20 25 30 10 20 30 40 atomic atomic # 1st IE IE

Graph 4: Atomic # vs. 1st ionization energy

SLIDE 2

2

Which element has the highest value for First Ionization Energy?

He

Which element has the lowest value for First Ionization Energy?

Cs (or Fr)

The relative ability of an atom to attract electrons within a chemical bond Which are more likely to attract an e-, metals or nonmetals? nonmetals

Electronegativity

Metals Nonmetals weaker pull lose e- large atoms: e- in valence shell feel _____________ from nucleus generally __________ to make ion w/octet stronger pull smaller atoms: e- in valence shell feel _________________ from nucleus gain or share e- generally _________________ to make ion w/octet

atomic # # vs.

• vs. EN

EN

0.5 1 1.5 2 2.5 3 3.5 4 4.5 10 20 30 40 atomic # EN EN

Atomic # vs. electronegativity 3 4 5 6 7 8 9 11 17 19 35 37 38 1

• EN ↑ across row (other than noble gases)
• # p+ in nuclei ↑, so valence e- feel strong (+) pull from

nucleus

1 H He 2 Li Be B C N O F Ne 3 Na Mg Al Si P S Cl Ar 4 K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr 5 Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe 6 Cs Ba Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn 7 Fr Ra Rf Ha Sg Ns Hs M t Uun (6) La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu (7) Ac Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr

• EN ↓ down column
• larger atoms, valence e- further from nucleus, weak

pull on e-

increases increases

How does EN change across period: How does EN change within group:

Which element has the highest electronegativity?

F

Which element has the lowest electronegativity (neglecting noble gases)?

Fr

Increasing size

SLIDE 3

3

atomic atomic # # vs.

• vs. atomic

atomic radius radius

0.5 1 1.5 2 2.5 3 3.5 10 20 30 40 atomic atomic number atomic atomic radius radius

Atomic # vs. radius

Trend:

• 1. Atomic radii _____down a group
• 2. Atomic radii _____across period

Why?

• 1. __________ in orbital sizes as energy level ↑

↑

↓

• Valence e- _____________________
• The atomic radius __

Increase

• 2. Across a period:

drawn closer to nucleus ↓

• Same # core e- blocking pull from nucleus
• Nuclear charge ↑ due to more p+

Periodic Trends of Atomic Properties

Metals = Elements that have partially filled lose Nonmetals = Elements that have partially filled gain Low IE, low EN, large atoms high IE, high EN, small atoms s- or d-sublevel orbitals Tend to ______ electrons p-sublevel orbitals Tend to _______ electrons F is the most active nonmetal:

• High EN
• High IE
• Very small radius = nuclear charge close to valence e-

Fr is the most active metal:

• Low EN
• Low IE
• Very large radius = nuclear charge far from valence e-

Which nonmetal is most likely to take electrons from a metal?

Which metal will most easily lose its valence electrons to a nonmetal?

1

H He

2

Li Be B C N O F Ne

3

Na Mg Al Si P S Cl Ar

4

K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr

5

Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe

6

Cs Ba Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn

7

Fr Ra Rf Ha Sg Ns Hs M t Uun

(6)

La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu

(7)

Ac Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr

increases increases

trend in nonmetal reactivity trend in metal reactivity

1

H He

2

Li Be B C N O F Ne

3

Na Mg Al Si P S Cl Ar

4

K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr

5

Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe

6

Cs Ba Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn

7

Fr Ra Rf Ha Sg Ns Hs M t Uun

(6)

La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu

(7)

Ac Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr

increases increases

SLIDE 4

4

1

H He

2

Li Be B C N O F Ne

3

Na Mg Al Si P S Cl Ar

4

K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr

5

Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe

6

Cs Ba Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn

7

Fr Ra Rf Ha Sg Ns Hs M t Uun

(6)

La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu

(7)

Ac Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr

increases increases

trend in nonmetallic nature: trend in metallic nature:

1

H He

2

Li Be B C N O F Ne

3

Na Mg Al Si P S Cl Ar

4

K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr

5

Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe

6

Cs Ba Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn

7

Fr Ra Rf Ha Sg Ns Hs M t Uun

(6)

La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu

(7)

Ac Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr

increases increases