Unit 2 Notes 2

Question 1

Size of Atoms

Answer 1

The size of atoms as you move down a group increases. Every step down a group adds a new shell

Question 2

Shielding Effect

Answer 2

• core e- reduce the attraction b/w the nucleus + the valence e- which allows the valence e- to drift out causing the size of the atom to increase.

Question 3

what happens to the size of the atoms as we move from the L to R of the row?

Answer 3

The size decreases be the nuclear charge increases

Question 4

Groups 3-12 - Transitional Metals

Answer 4

• form brightly coloured compounds.
• I or 2 valence electrons
  Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn
  Y, Zr, Mo, Nb,Tc, Ru, Rh, Pd, Ag, Cd
  Hf, Ta, W, Re, Os, Ir, Pt, Au, Hg
  Rf, Db,Sg, Bh, Hs, Mt, Ds, Uuu,Uub

Question 5

Non- Metals

Answer 5

• located to the right of the staircase
• brittle nonconductors

Question 6

Metals

Answer 6

• located to the left of the staircase
• conduct electricity
• malleable
  Li Be
  Na Mg SC
  K Ca
  Rb Sr
  Cs Ba
  Fr Ra

Question 7

Metalloids

Answer 7

-elements located along the staircase
- have characteristics of both metals and non- metals (don’t heat up when conducting electricity!

Question 8

Atomic #

Answer 8

• indicates the # of protons (p+) in the nucleus
• defines what element an atom is
• for a neutral atom it also indicates the # of electrons (e-)
  1 <– atomic #
  H
  1.0086- <– mass #

Question 9

Mass #

Answer 9

-indicates
-the # of p+ + n° (neutrons)
#n° =mass# - #p+

Question 10

Isotopes

Answer 10

-atoms of the same element w/ different atomic masses
-ie the same # of p+ but different # of n°

Question 11

Average Mass.

Answer 11

mass= %Isotope A (mass A) +%Isotope b (mass b)
———————————————
100

Question 12

Lewis Diagrams

Answer 12

Lewis diagrams show the valence e- in an atom. Consist of the symbol + dots. The symbol represents the nucleus + core. e- (not in valence shell). The dots represent valence e-