1. What is the change in atomic mass number when an atom emits an alpha particle?
A) decreases by 2
B) decreases by 4
C) decreases by 2
D) increases by 4

2. If an isotope decays by the process of beta emission __.
A) the mass number changes
B) the atomic number chnages
C) protons are given off
D) the number of neutrons remains the same

3. 56/25 Mn -> __ + 0/-1 e
A) 56/27 Co
B) 37/25 Mn
C) 56/26 Fe
D) 58/24 Cr

4. Which of the following naturally occurring radioisotopes would be most useful in dating objects though to be a million years old?
A) carbon-14; t1/2=5.73x10^3
B) potassium-40; t1/2=1.28x10^9
C) thorium-23; t1/2=25 days
D) radon-222; t1/2=3.8 days

5. The production of carbon-14 __.
A) takes place in the upper atmosphere
B) is mostly due to fallout from nuclear explosions
C) occurs to a large extent in nuclear reactors
D) is caused by photosynthesis in plants

Please help.. I will mark brainliest. Thanks!!

1. Decreases by 4. (B)

2. The atomic number changes. (B)

3. 56/26 Fe. (C)

4. Potassium-40;t1/2=25 days. (B)

5. Takes place in the upper atmosphere. (A)

the best answer is d because the strong cohesion is caused by the ability of water molecules to undergo hydrogen bonding.

a is incorrect because when water solidifies, it becomes   ice, which expands and occupies a bigger volume for the same mass of water in its liquid state.

b is incorrect because water has high surface tension. besides bonding to itself it hydrogen bonds to other molecules at the top decreasing possibility for breaking of attractive forces.

c is incorrect because the water molecule has oxygen which is highly electronegative and so pulls the electron pair towards itself creating a dipole moment, making the molecule polar.

e is incorrect because water has strong adhesion, ability to stick to other molecules such as glass because of this molecules having stronger hydrogen bonding than water.