Answer:
The correct answer is option A: they are isotopes.
Explanation:
From atom X we know that the number of protons is 7 and the number of neutrons is 7 and from atom Z we know that the number of protons is 7 and the number of neutrons is 8.
Since the number of protons of atom X and atom Z is the same, we have that atom X and atom Z is the same element. The difference in the number of neutrons tells us that atom X and atom Z are isotopes. Remember that an isotope is one element that has atoms with different numbers of neutrons.
The mass number is given by:
Where <em>n</em> is the number of neutrons and <em>p </em>is the number of protons.
For atom X and atom Z we have:

Hence, they have a different mass number.
We know that the element with 7 protons is nitrogen. The first isotope is
and the second isotope is
. Both isotopes are stables (they are not radioactive).
Therefore, the correct answer is option A: they are isotopes.
I hope it helps you!
Answer: 4 x 106
That’s how you write forty million in scientific notation.
Answer:
Angular acceleration = 23.68 rad / s²
Explanation:
Given that,
acceleration = 9m/s²
Therefore acceleration of string is 9m/s²
since string is constant in length
cylinder of radius 38.0 cm = 0.38m
Angular acceleration = a / r
Angular acceleration = 9 / 0.38
= 23.68 rad / s²
Angular acceleration = 23.68 rad / s²