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4vir4ik [10]
3 years ago
8

Why is helium considered as a noble gas

Chemistry
2 answers:
dolphi86 [110]3 years ago
7 0
Noble gases are known for having a full outer shell of electrons which helium has as it has two electrons its first electron shell is completely filled

larisa [96]3 years ago
3 0
Helium is  considered a noble gas because it has 8 valence electrons, as well as it also is a stable element. Meaning that it consists of a full octet. 
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What is the main side reaction that competes with elimination when a primary alkyl halide is treated with alcoholic potassium hy
Elanso [62]

Answer:

The main competing reaction when a primary alkyl halide is treated with alcoholic potassium hydroxide is SN2 substitution.

Explanation:

The relative percentage of products of the reaction between an alkyl halide and alcoholic potassium hydroxide generally depends on the structure of the primary alkylhalide. The attacking nucleophile/base in this reaction is the alkoxide ion. Substitution by SN2 mechanism is a major competing reaction in the elimination reaction intended.

A more branched alkyl halide will yield an alkene product due to steric hindrance, similarly, a good nucleophile such as the alkoxide ion may favour SN2 substitution over the intended elimination (E2) reaction.

Both SN2 and E2 are concerted reaction mechanisms. They do not depend on the formation of a carbocation intermediate. Primary alkyl halides generally experience less steric hindrance in the transition state and do not form stable carbocations hence they cannot undergo E1 or SN1 reactions.

SN2 substitution cannot occur in a tertiary alkyl halides because the stability of tertiary carbocations favours the formation of a carbocation intermediate. The formation of this carbocation intermediate will lead to an SN1 or E1 mechanism. SN2 reactions is never observed for a tertiary alkyl halide due to steric crowding of the transition state. Also, with strong bases such as the alkoxide ion, elimination becomes the main reaction of tertiary alkyl halides.

7 0
3 years ago
What is the differnce between the atomic number and the mass number of an element?
MrRissso [65]
Atomic number refers to the number of protons within the nuclei of an element's atoms (and therefore the number of electrons) while mass number refers to the number of protons and neutrons within the nucleus.
8 0
3 years ago
chlorine has two naturally occurring isotopes, Cl-35 and Cl-37. The atomic mass of chlorine is 35.45. Which of these two isotope
Sliva [168]
Cl-35, as the atomic mass of Chlorine (35.45) is closer to the number 35 than to the number 37. A higher abundance of CL-35 isotope would have caused the atomic number (which is an average of the values of all isotopes of a substances taking relative abundance into consideration) to decrease from 36, which would appear to be the average.
5 0
3 years ago
A box with a mass of 3.5 kg is pushed along a table. If the net force on the box is 35 Newtons, what is the acceleration of the
Vesnalui [34]

Answer:

<h2>10 m/s²</h2>

Explanation:

The acceleration of an object given it's mass and the force acting on it can be found by using the formula

a =  \frac{f}{m}  \\

m is the mass

f is the force

From the question

mass = 3.5 kg

force = 35 N

We have

a =  \frac{35}{3.5}  \\  = 10

We have the final answer as

<h3>10 m/s²</h3>

Hope this helps you

8 0
3 years ago
Need help balancing these ​
kari74 [83]
The answer would be 1,3,1,3
3 0
3 years ago
Read 2 more answers
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