1.)Boron
2.)Cadmium has 48 electrons not 121 Mercury has 80 And Copernicum so they all have no 121 electrons
3.)Hydrogen
Answer : The volume of container will be 44.8 L
Explanation :
At STP condition,
The temperature and pressure are 273 K and 1 atm respectively.
As we know that at STP, 1 mole of substance occupies 22.4 L volume of gas.
As per question,
1 mole of nitrogen gas occupies 22.4 L volume
and,
1 mole of neon gas also occupies 22.4 L volume
Thus, total volume will be:
Total volume of container = 22.4 + 22.4 = 44.8 L
Hence, the volume of container will be 44.8 L
Answer:
<h2>4.55 L</h2>
Explanation:
The new volume can be found by using the formula for Boyle's law which is

Since we're finding the new volume

We have

We have the final answer as
<h3>4.55 L</h3>
Hope this helps you
This problem is asking for the percent by mass of hydrogen in hydrofluoric acid. At the end, the answer turns out to be D. 5% as shown below:
<h3>Percent compositions:</h3>
In chemistry, percent compositions are used for us to know the relative amount of a specific element in a compound. In order to do so for hydrogen, we use the following formula, which can also be applied to any other element in a given compound:

Where
stands for the atomic mass of hydrogen and
for the molar mass of hydrofluoric acid. In such a way, we plug in the atomic masses of hydrogen (1.01 g/mol) and fluorine (19.0 g/mol) to obtain:

Learn more about percent compositions: brainly.com/question/12247957