Unit 1.8 Flashcards
What are valence electrons?
The electrons that are in the outermost electron shell
What are valence shells?
The shell that combines electrons furtherest from the nucleus
1st Electron Shell
2 Electrons
2nd Electron Shell
8 Electrons
3rd Electron Shell
8 Electrons
4th Electron Shell
18 Electrons
5th Electron Shell
18 Electrons
6th Electron Shell
32 Electrons
7th Electron Shell
32 Electrons
Why are noble gasses stable?
They are usually un-reactive because they have a full valence shell(farthest to the right)
What two types of elements combine in ionic bonding?
Non-metals and metals
What happens to metals in an ionic bond?
Lose electrons and become + charged
What happens to non-metals in an ionic bond?
Gain electrons and become - charged
What is covalent bonding?
Happens when 2 or more non-metals elements combine by sharing electrons
- Which of the following isotopes has 30 neutrons?
(A) Manganese-55
(B) Nitrogen-15
(C) Phosphorus-30
(D) Zinc-65
Answer: All of these isotopes are written with their mass number. The mass number is the number of protons plus neutrons. Manganese has 25 protons; therefore, 55-25 = 30 neutrons.
2 .The ionization energy and atomic radius for aluminum is 578kJ/mol and 143 pm, respectively. What is the most likely ionization energy and atomic radius for silicon?
(A) 496 kJ/mol and 110 pm
(B) 496 kJ/mol and 180 pm
(C) 789 kJ/mol and 110 pm
(D) 789 kJ/mol and 180 pm
Answer: When comparing elements in the same row, one must look at the number of protons the element has. Since silicon has more protons in its nucleus, it is better at attracting its electrons than aluminum is. This makes the first ionization energy greater and the radius smaller.
- What is the electron configuration for Fe^2+?
(A) 1s^2 2s^2 2p^6 3s^2 3p^6 3d^6
(B) 1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^4
(C) 1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^6
(D) 1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^8
Answer: When electrons are removed from atoms, they are removed from the valence shell, which for iron is the fourth energy level. The valence electrons are the electrons in the highest energy level. Therefore, the electron configuration of Fe^2+ is 1s^2 2s^2 2p^6 3s^2 3p^6 3d^6.
- Given the following information, a 1.00 g sample of which of the following substances contains the greatest amount of chlorine?
(A) Li Cl
(B) K Cl
(C) Na Cl
(D) Rb Cl
Answer: The percent composition of chlorine in LiCl is greatest, therefore, in samples of the same mass, the mass of chlorine will be greatest in the sample with the greatest mass percent.
- Which of the following correctly identifies which has the greater first ionization energy, Na or Mg, and supplies the best reason?
(A) Mg, because of its greater nuclear charge.
(B) Mg, because it has a full sub-shell of electrons.
(C) Na, because it has a greater electronegativity
(D) Na, because of its greater mass.
Answer: When comparing two elements in the same period, one must consider the nuclear charge. The nuclear charge refers to the number of protons, of which magnesium contains more. with more protons, Mg has a greater force of attraction on its electrons.
