Explanation:
Ionization energy is defined as the energy required to remove the most loosely bound electron from a neutral gaseous atom.
When we move across a period from left to right then there occurs a decrease in atomic size of the atoms. Therefore, ionization energy increases along a period.
But when we move from top to bottom in a group then there occurs an increase in size of the atoms. Hence, ionization energy decreases along a group.
(a) As Sb, Sn and I are all period 5 elements. Hence, these elements are arranged in order of increasing 
as follows.
Sn < Sb < I
(b) As Sr, Ca, and Ba are all elements of group 2a. Hence, these elements are arranged in order of increasing as follows.
Ba < Sr < Ca
The answer is 1/8.
Half-life is the time required for the amount of a sample to half its value.
To calculate this, we will use the following formulas:
1.
,
where:
<span>n - a number of half-lives
</span>x - a remained fraction of a sample
2.
where:
<span>
- half-life
</span>t - <span>total time elapsed
</span><span>n - a number of half-lives
</span>
The half-life of Sr-90 is 28.8 years.
So, we know:
t = 87.3 years
<span>
= 28.8 years
We need:
n = ?
x = ?
</span>
We could first use the second equation, to calculate n:
<span>If:
,
</span>Then:
⇒
⇒
<span>⇒ n ≈ 3
</span>
Now we can use the first equation to calculate the remained amount of the sample.
<span>
</span>⇒
⇒
<span>
</span>
Answer:
The rain containing excess of acid I called acid rain
That is false (please mark me brainliest)
