Noble gases
Explanation:
Electronic configuration 1s² 2s² 2p⁶
The element belongs to the group of the noble gases.
- The noble gases have complete outer shell configuration of their atoms.
- we can infer that the configuration above is for an element in the p-block because the last sub-level filled is the p-orbital.
- The elements therefore belongs to the p-block
- The block is from group 111A to O
- Only the halogens and noble gases fits this picture from the option.
- The outer most p-subshell have three orbitals requiring 6 electrons to fill them up.
- This makes a complete and stable configuration.
- The highest energy level of 2 is also made up of 8 electrons, an octet.
- This is why we can conclude that they are noble gases.
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Noble gas brainly.com/question/1781595
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In order for the molecule to change phase from liquid to gas and evaporates, it needs to overcome the force from other molecules around it. as the force bigger evaporation gets harder. so e has the highest force and higher boiling point.
Answer:
0.4 M
Explanation:
The process that takes place in an aqueous K₂HPO₄ solution is:
First we <u>calculate how many K₂HPO₄ moles are there in 200 mL of a 0.2 M solution</u>:
- 200 mL * 0.2 M = 40 mmol K₂HPO₄
Then we <u>convert K₂HPO₄ moles into K⁺ moles</u>, using the <em>stoichiometric coefficients</em> of the reaction above:
- 40 mmol K₂HPO₄ *
= 80 mmol K⁺
Finally we <em>divide the number of K⁺ moles by the volume</em>, to <u>calculate the molarity</u>:
- 80 mmol K⁺ / 200 mL = 0.4 M
The answers are
The age of the oldest stars
How fast distant galaxies are moving away from us
Patterns of background radiation.
Explanation:
The Astronomers calculate the age of the universe by looking for oldest stars, and by measuring the rate of expansion of the universe and back to big bang.
The Astronomers used the techniques like the age of oldest stars, how fast the distant galaxies are moving away from us, patterns of background radiation and along with the Big Bang as reference point, they estimate that the universe may be approximately 12 billion years old.
