Using the model, what is the mass of the atom pictured?
A)3amu
B)5amu
C)7amu
D)9amu

with 20 protons (p=20) and 22 neutrons (n=22)? 47 ... Listed below are the charges and masses of four ... a) +2,2 amu c ) +1, 1 amu least b) ... pudding” Model.

Explanation:

7amu

Explanation:

Atoms are composed of three particles.  The proton, neutron, and electron.  

The mass of the atom in amu is just the number of protons and neutrons in the nucleolus since they both have a mass of about 1 amu.  Electrons are not counted since they have an incredibly small mass that ultimately does not matter.  

This atom has 3 protons (positively charged particle) and 4 neutrons (particle with no charge) which together gives a mass of 7 amu.

1. the question asks the most appropriate, which seems to rule out "all of the above." your choice appears to be the correct one.

2. the protocol described is good for identifying correlation, but not cause and effect. for cause/effect, you need to devise a protocol that will assign the treatment (or not) to groups that have essentially the same "demographics" with respect to all the other variables. your choice regarding control group seems appropriate. random assignment of treatment (choice d) may be appropriate also. (i think you can argue that b and d are just different descriptions of the same method.)

3. d will randomize the birds, but may not guarantee there are 10 in each group. e will do both, so seems the better choice.

comment on question 2

based on the problem statement, it seems clear that confident, attentive drivers are more likely to use daytime running lights. so, the protocol might need to be devised in such a way that the lights would be turned on or off without the driver's knowledge. (an attentive driver will figure it out.) assigning a confident, attentive driver to a group required to drive without running lights might mess with his/her confidence and attentiveness. you don't want your experiment to do that. (nor do you want the experiment to subject a driver to greater risk of accident as a consequence of driving without running lights.) experiments involving human safety are always problematic.

periodic trends is an atom that gets larger as the number of electronic shells increase, the radius of atoms increases as you go down a certain group in the periodic table of elements. in general, the size of an atom will decrease as you move from left to right of a certain period.