Electrons
How many valence electrons does Nitrogen have?
Five valence electrons. (2-5)
What is true if an atom is neutral?
# of protons = # of electrons
Metals (Left - except H); Nonmetals (Right); Metalloid/Semi-Metals (around bold step-like line except Al)
What are the 2 liquids in the PT?
Hg - metal & Br - nonmetal
How do I know when we have a nuclear reaction (vs chemical reaction).
An element changes into a new element (transmutation) / different elements on reactant and product side.
How many energy levels does Calcium have?
Four energy levels (2-8-8-2 = 4# or period 4)
What happens to a the size of an atom if you lose or gain electrons?
Lose - decrease size / Gain - Increase size
Which group (#/name) has all 3 phases of matter?
Group 17 - Halogens
Why are metals and ions able to conduct electricity?
Metals - mobile electrons / Ions - mobile ions
How much energy is produced in a nuclear reaction compared to a chemical reaction.
Nuclear reactions produced a lot more energy than a chemical reaction.
Draw the electron-dot structure of Neon (Ne)?
(Drawing)
What happens to Aluminum if it loses 3 e-?
Now has 10e- (instead of 13); Decreases in size; becomes a +3 ion (Al +3); e- configuration changes to 2-8 (looks like Ne)
Name the 7 diatomics.
H2, N2, O2, F2, Cl2, Br2, I2
What is the pattern in atomic radius (size) in a period and group as atomic # increases?
As atomic # increases - atomic radius decreases in a period (more p+ so more attraction for e-)/ group increases (more energy levels)
If given two electrodes (+ and -) - what nuclear emissions will be attracted?/ Which substance has the greatest penetrating power?
+ ion --> attracts - so a Beta; - ion --> attracts + so Alpha; Gamma - not attracted
Penetrating power = gamma > beta > alpha
(Drawing)
What can we say about S -2?
It is a - 2 ion because it gain 2 e- so it has 18 e- now so looks like Ar (2-8-8); also increase in size.
What must we remember about group 18 - Noble gases?
They are stable - have a full valence shell. (Generally atoms - lose/gain/share e- to look like noble gases.)
Where are the most reactive metals and nonmetals found?
metals -lower left (near Fr) / nonmetals - upper right (near F)
Write the natural decay reaction for I-131?
131/53 I --> 0/-1 e. +. 131/54Xe
How is the bright-line spectrum produced?
Produced when e- move from a high to a low energy level. (From excited state to ground state.)
Why do elements want to lose or gain e- ? / Who do they want to look like?
They want to be stable - look like a noble gas (group 18 element)
What are allotropes?
Forms of the same element with different physical/chemical properties - (generally b/c atoms combined in different structures).
Direct relationship (Inc EN = IN IE) - the more attraction for electrons , the more energy it takes to remove a valence e-
(As atomic # increases -->Period = Inc EN/IE & Group = Dec EN/IE - electrons farther from nucleus)
What is the original mass of 2g of Cs-137 after 90.6y?
16g. (1) 90.6/30.2 = 3 so (2) 2 --> 4 ---> 8 --> 16g