SECTION 2 - PERIODIC PROPERTIES

Question 1

Dimitri Mendeleev & Lothar Meyer

Answer 1

Proposed the periodic law arranging elements in increasing atomic mass

Question 2

Henry Mosely

Answer 2

Discovered a systematic relation between wavelength and atomic number and rearranged Mendeleev’s elements by atomic number instead of mass

Question 3

Groups

Answer 3

Columns in the table (vertical axis) with similar properties, same number of valence electron

Question 4

Period

Answer 4

Rows in the table (horizontal axis)

Question 5

Principle quantum number trend on periodic table

Answer 5

Atomic number increases from left to right in periodic table and top to bottom in group

Question 6

Atomic radius:

Answer 6

Size of atom

Question 7

3 types of atomic radius:

Answer 7

• Covalent radius
• Ionic radius
• Metallic radius

Question 8

Covalent radius

Answer 8

Distance between the nuclei of 2 nonmetal atoms joined by a single covalent bond

Question 9

Ionic radius

Answer 9

Distance between nuclei of metal and nonmetal atoms joined by ionic bond

Question 10

Metallic radius

Answer 10

One half of the distance between the nuclei of two atoms in contact in the crystalline solid metal.

Question 11

Influences of variations in atomic radius (2)

Answer 11

• Changes in principle quantum number (bigger n = further from nucleus)
• Changes in effective nuclear charge (bigger Zeff (more positive/electrons held more tight to nucleus) = closer to nucleus and smaller orbitals)

Question 12

How to find core electron

Answer 12

Subtract preceding noble gas from desired atomic number

Question 13

Anion size (ionic radius)

Answer 13

LARGER than the atom from which they are formed because when a nonmetal gains electrons to form anions, the total number of electrons increase around the nucleus and become greater than the amount of protons so repulsion of electrons increase (the more negative the charge, the larger the anion size, more repulsion and smaller Zeff)

Question 14

Cation size (ionic radius)

Answer 14

SMALLER than the atom from which they are formed because when a metal loses electrons to form cations, total number of electrons will decrease around nucleus and each electron feels a larger attraction to protons in nucleus (the more positive the charge, the smaller the cation size and larger Zeff size)

Question 15

Ionization energy (IE)

Answer 15

Amount of energy needed to remove electron from atom

Question 16

Despite the trend in ionization energy, why is the IE of B lower than Be

Answer 16

Because the s orbital is fully occupied in BE whereas B has 1 electron in p so B makes it easier to remove

Question 17

Electron affinity (EA)

Answer 17

Energy change that results from adding an electron to a neutral atom in gas phase

Question 18

Why are noble gas elements hard to add electrons

Answer 18

Because they already have a full stable shell

Question 19

Van der Waals radius

Answer 19

Distance between two nuclei that are not bound by bond. This is also known as nonbonding atomic radius