Is it true or false I need help.

A student explained to the class that helium has 8 valence electrons because it is in group 18. Is the student correct?

lys-0071 [83]

The student is incorrect because helium has 2 valence electrons and it's in group 18 because the first energy level is full. Although helium is placed in Group 18 which generally has 8 valence electrons, it does not have 8 valence electrons as the student suggested. It was grouped together with the noble gases because it exhibits similar properties with them.

5 0

3 years ago

(a)-Use Lewis symbol store present there action that occurs between Ca and F atoms. (b)-What is the chemical formula of the most

Charra [1.4K]

Answer:

(a) The Lewis structure is shown in the image below.

(b) $CaF_2$

(c) Calcium loses 2 electrons to 2 atoms of fluorine and these 2 atoms of fluorine accepts each electron to form ionic bond.

(d) Calcium atom loses electrons.

Explanation:

Calcium is the element of second group and forth period. The electronic configuration of Calcium is - 2, 8, 8, 2 or $1s^22s^22p^63s^23p^64s^2$

There are 2 valence electrons of Calcium.

Fluorine is the element of group 17 and second period. The electronic configuration of the element fluorine is - 2, 7 or $1s^22s^22p^5$

There is 1 valence electron of fluorine.

The Lewis structure is drawn in such a way that the octet of each atom is complete.

Thus, calcium loses 2 electrons to 2 atoms of fluorine and these 2 atoms of fluorine accepts each electron to form ionic bond. This is done in order that the octet of the atoms are complete and they become stable.

Thus, the formula of calcium chloride is $CaF_2$ .

(a) The Lewis structure is shown in the image below.

(b) $CaF_2$

(c) Calcium loses 2 electrons to 2 atoms of fluorine and these 2 atoms of fluorine accepts each electron to form ionic bond.

(d) Calcium atom loses electrons.

5 0

3 years ago

Compare the use of renewable resources and nonrenewable resources in the production of electricity in the united states, based o

Tamiku [17]

Answer:Both renewable and nonrenewable resources can be used to generate electricity, as a heat source, and for vehicle fuel. ... The use of renewable resources typically has less environmental impact in the form of pollution than the use of nonrenewable resources.

Explanation:

5 0

3 years ago

I need on that question at the bottom of the page?

anzhelika [568]

The hills and valleys decrease the height and speed of the ride. This means that the graph has a negative correlation.

By the way, I think you may have plotted your points incorrectly. The directions said to connect them all with a smooth line or curve.

Also, this is not high school chemistry. This is more likely to be elementary school science. Just make sure that you put your questions in the correct categories next time! :)

3 0

3 years ago

Sodium will do an ionic with

Nana76 [90]

Answer : Bromine
Step by step: Bromine

8 0

3 years ago