The proton, neutron and electrons in the atom of the element represented by the symbol 231Y89 are: A. 89,231 and 89
B. 142, 89 and 142
C. 89, 142 and 89
D. 89, 320 and 320

Protons = 89

Neutrons = 142

Electrons = 89

Option C

Explanation:

Hello,

Were required to find the proton, neutron and electron of an element Y

The atomic mass of element Y is composed of the protons and neutrons while the atomic number is the exact amount of protons present in the element.

Element = ₈₉²³¹Y

Atomic number = 89

Number of protons = 89

Number of electrons = 89

Atomic mass = 231

Atomic mass = protons + neutrons

231 = 89 + neutrons

Neutrons = 231 - 89

Neutrons = 142

Therefore the number of protons is 89, number of neutrons is 142 and number of electrons is 89.

Note: for an electrically neutral atom, the number of protons must be equal to the number of electrons

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.