Nuclear Atom
If a sodium has 10 electrons, what is its charge?
1+
What drives periodic trends across a period and what drives periodic trends down a group?
across a period = number of protons
down a group = shell number
write the decay equation for aluminum-28
See figure 1 (100)
H has a smaller radius, it has electrons in shell 1 vs. shell 2 for F
How many valence electrons does gold (Au) have?
1 (1 electron in the s subshell - f and d are full)
Assuming boron-10 is a neutrally charged atom how many electrons, protons, and neutrons does it have?
p = 5 , n = 5, e = 5
Which element has a larger radius and why?
Na, K, Rb or Cs?
Cs because it is furthest down the group (period 6) which means it has valence electrons in a higher shell number (6) making the radius larger
Neon-20 is the beta decay product of what isotope?
Flourine-20
See figure 2 (200)
Blue indicates areas of low electron density, and green indicates a middling amount of electron density.
The difference in the images is due to the electronegativity of the atom H is combined with. If we look at H2, H is combined with H and so there is no electronegativity difference, and they equally share the electrons.
If we look at HCl, hydrogen is less electronegative than chlorine and so the Cl atom attracts the electrons towards itself (giving it an orange color and a larger size) and away from the H atom (leaving it electron poor, smaller, and blue in the image).
Explain (completely) what is meant by 4d^8
(please forgive Jeopardy's inability to do a superscript)
d = subshell ID, the area of space we would expect to find the electrons
8 = number of electrons in the subshell
carbon-12, carbon-13, and carbon-14 are all examples of what? What is the same and what is different between these three?
Define the following and describe the trend down group/across period:
- electron affinity (Eea)
- ionization energy (Ei)
electron affinity = energy released when an electron is added to an atom (a larger electron affinity means that the atom is more stable when an electron is added). No trend down group/across period EXCEPT group 17 has a large Eea.
ionization energy = energy needed to overcome the electrostatic attraction (Felectrostatic) and remove one electron to form a cation. Decreases down a group, increases across a period
Uranium-235 is the alpha decay product of what isotope?
Plutonium - 239
See figure 3 (300)
F, Cl and Br are in the same group and radius increases down group due to increasing number of shells so F is smaller than Cl which is smaller than Br
How many electrons will Aluminium want to gain or lose and why?
Lose 3 to reach octet (stable neon electron configuration)
What is the difference between mass number (A) and atomic number (Z).
Mass number = protons+neutrons
Atomic number = # protons
silicon, phosphorous, sulfur, or helium?
sulfur - moving across the period (so they all have similar shielding) sulfur has more protons meaning it's effective positive charge from the nucleus is stronger, increasing its ability to attract electrons in a bond (X)
*remember noble gases have X = 0 because of full valence - they don't attract electrons in a bond
Predict the decay product of polonium-212
alpha (z = 84 which is > 82)
See figure 4 (400)
O, S, and Se are all in the same group and electronegativity decreases down group because the shell number increases (increasing shielding and making it harder to attract electrons in a bond). This explains why Se has the lowest electron density (yellow) and O has the highest electron density (red)
What is the predicted charge for selenium?
2- (gain 2 electrons to reach 8 valence electrons)
p = 33, e = 36, neutrons = 34
Explain why potassium chloride will never form a potassium anion (Na–) and chlorine cation (Cl+) in terms of Eea and Ei
Eea - Chlorine is group 17, which has an appreciable Eea (meaning it will become much more stable when adding an electron) because it is a halogen (one electron away from achieving a full octet) while Na is group 1 and has no appreciable Eea.
Ei - ionization energy increases across a period because the pull from the nucleus is stronger, the Ei for Na is much lower because it only has 11 protons compared to 17 protons in Cl so it's easier to remove an electron from Na than Cl
predict the decay product for tecnitium-93
beta (z = 43 which is <82)
See figure 5 (500)
arsenic will be larger (3rd shell so bigger radius) so it will not be able attact as many electrons making it electron poor (blues) compared to nitrogen.
Is the following element stable? If not how many electrons will it gain or lose?
Tungston (W)