Answer:
The nucleus of an atom is made up of positively charged protons and neutrally charged neutrons. The nucleus determines which element an atom is, based on the number of protons. For example, only Oxygen has 8 protons, Carbon has 6 protons, etc. The nucleus is about 1/100,000 of the size if the whole atom.
They both have seven electrons in their outer shell.
False. Solids have a definite shape and volume. Cutting a paper (solid) in half will alter the shape of the original solid and give it a new shape and volume instead. A solid will always have a definite shape. If not, it's not a solid.
Explanation:
(1) When a proton is converted into neutron then the positron emission takes place as follows.
![^{1}_{1}p \rightarrow ^{1}_{0}n + ^{0}_{+1}e](https://tex.z-dn.net/?f=%5E%7B1%7D_%7B1%7Dp%20%5Crightarrow%20%5E%7B1%7D_%7B0%7Dn%20%2B%20%5E%7B0%7D_%7B%2B1%7De)
A positron is represented by the symbol
. Therefore, when a positron emission occurs then the resultant nuclei atomic number decreases by a unit mass.
General equation representing positron emission is as follows.
![^{M}_{Z}A \rightarrow ^{M}_{Z-1}B + ^{0}_{+1}e](https://tex.z-dn.net/?f=%5E%7BM%7D_%7BZ%7DA%20%5Crightarrow%20%5E%7BM%7D_%7BZ-1%7DB%20%2B%20%5E%7B0%7D_%7B%2B1%7De)
Hence, Fluorine-18 decays by positron emission as follows.
![^{18}_{9}F \rightarrow ^{18}_{8}O + ^{0}_{+1}e](https://tex.z-dn.net/?f=%5E%7B18%7D_%7B9%7DF%20%5Crightarrow%20%5E%7B18%7D_%7B8%7DO%20%2B%20%5E%7B0%7D_%7B%2B1%7De)
Therefore, when 18F undergoes positron emission, the product nucleus is,
.
(2) Expression for the half-life of a
isotope is as follows.
![t_{\frac{1}{2}} = \frac{0.693}{\lambda}](https://tex.z-dn.net/?f=t_%7B%5Cfrac%7B1%7D%7B2%7D%7D%20%3D%20%5Cfrac%7B0.693%7D%7B%5Clambda%7D)
Initial activity, (
) = 4.00 millicuries
Activity after 95% = ![4.00 - 4.00 \times \frac{95}{100}](https://tex.z-dn.net/?f=4.00%20-%204.00%20%5Ctimes%20%5Cfrac%7B95%7D%7B100%7D)
= 0.20 millicuries
![\lambda = \frac{2.303}{t} log \frac{[N]_{o}}{[N]_{t}}](https://tex.z-dn.net/?f=%5Clambda%20%3D%20%5Cfrac%7B2.303%7D%7Bt%7D%20log%20%5Cfrac%7B%5BN%5D_%7Bo%7D%7D%7B%5BN%5D_%7Bt%7D%7D)
t = 7.912 hrs
Thus, we can conclude that it will take 7.91 hrs for 95% of the 18F to decay.
Answer:
<em>The N given in the question is normality while the M given in the question designates morality.
</em>
Explanation:
There are minor differences between both the terms normality and morality given in the question and both are inter convertible.
When one litre of solution is considered when the particles of solute in that litre would show the morality of the solution while when one litre of Solution is considered and equivalent are given then it is known as normality.