Chapter 2: The Periodic Table

Question 1

List 10 features of alkali metals.

Answer 1

• group 1 (first column of the periodic table)
• densities are lower than most other metals
• 1 valence electron
• low Zeff
  
  • largest atomic radii within each period
  • low ionization energies
  • low electron affinities
  • low electronegativities
• form univalent cations
• react readily with nonmetals (especially halogens)

Question 2

List 3 features of alkaline earth metals.

Answer 2

• group 2 (second column of the periodic table)
• 2 valence electrons
• form divalent cations

Question 3

What are the active metals?

Answer 3

the alkali metals and alkaline earth metals (groups 1 and 2)

so reactive that they are not naturally found in their neutral state

Question 4

List 6 features of the chalcogens?

Answer 4

• group VIA or 16
• nonmetals and metalloids
• crucial for normal biological functions
• slightly less reactive than halogens
• 6 valence electrons
• small atomic radii and large ionic radii (due to proximity to metalloids)
• at high concentrations, many of these elements can be toxic/damaging

Question 5

List 3 biologically important chalcogens and describe their importance.

Answer 5

• oxygen
  
  • primary constituent of water, carbohydrates, other biomolecules
• sulfur
  
  • an important component of certain amino acids and vitamins
• selenium
  
  • important nutrient for microorganisms
  • has a role in protection from oxidative stress

Question 6

What are the physical properties of the halogens?

Answer 6

their physical properties are variable

they range from gases to liquid to solid forms

Question 7

Discuss the chemical reactivity of the halogens. (4)

Answer 7

• very high electronegativities
• high electron affinities
• especially reactive towards alkali and alkaline metals
• note naturally found in their neutral state, but rather as ions (halides) or diatomic molecules

Question 8

Answer 8

Question 9

Answer 9

Question 10

Answer 10

Question 11

Answer 11

Question 12

Answer 12

Question 13

Answer 13

Question 14

Answer 14

Question 15

atomic size/radius trend on period table

Answer 15

Question 16

effective nuclear charge

Answer 16

Question 17

ionization energy trend

Answer 17

Question 18

activation energy trend

Answer 18

Question 19

electronegativity

definition and trend

Answer 19

a measure of the attractice force an atom exerts on an electron in a chemical bond

Question 20

atomic radii