Which of these elements has the lowest melting point? (1) Li (3) K (2) Na (4) Rb

2 answers:

4 0

The answer is (4) Rb. From observation, we can find that these four elements are from first column. The melting point from top to the bottom is from high to low. So the answer is (4).

natali 33 [55]3 years ago

4 0

Answer: Option (4) is the correct answer.

Explanation:

It is known that on moving down a group there will be decrease in melting point of the element because of increase in number of shells.

As a result, outermost electrons move away from the nucleus due to which there will be decrease in force of attraction between the protons and valence electrons. Hence, there will be decrease in melting point.

Therefore, the given elements are of same group and Rb has largest atomic size.

Thus, we can conclude that Rb has the lowest melting point.

You might be interested in

Is a electron found in a subtonic particles in a atomic nucleus

Ksju [112]

An electron is found whizzing around the nucleus, so in subatomic particles.

3 0

3 years ago

Three of Louis Pasteur discovery

konstantin123 [22]

Pasteurization, vaccines against antrax and rabies, discovered the germ fermentation

7 0

3 years ago

_Al + _Fe(NO3)2 -->_Fe + __Al(NO3)3

romanna [79]

4Al+6Fe(NO3)2= 6Fe+4Al(NO3)3

4 0

3 years ago

What's the Balance equation for:<br>_C4H10O +_ O2--->_CO2+_H20

steposvetlana [31]

Answer:

C₄H₁₀O + 6O₂ ⇒ 4CO₂ + 5H₂O

Explanation:

Match the amount of reactants and products on both sides of the equation.

3 0

3 years ago

λmax for the π → π* transition in ethylene is 170 nm. Is the HOMO-LUMO energy difference in ethylene greater than or less than t

-Dominant- [34]

Answer:

the HOMO-LUMO energy difference in ethylene is greater than that of cis,trans−1,3−cyclooctadiene

Explanation:

The λmax is the wavelength of maximum absorption. We could use it to calculate the HOMO-LUMO energy difference as follows:

For ethylene

E= hc/λ= 6.63×10^-34×3×10^8/170×10^-9= 1.17×10^-18J

For cis,trans−1,3−cyclooctadiene

E= hc/λ=6.63×10^-34×3×10^8/230×10^-9=8.6×10^-19J

Therefore, the HOMO-LUMO energy difference in ethylene is greater than that of cis,trans−1,3−cyclooctadiene

8 0

3 years ago