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soldi70 [24.7K]
3 years ago
11

This element is a metalloid of Group IV. It has ____ valence electrons on the third energy level. Its name is ____, symbol____.

Its atomic number is ____ and its mass number is ____. This element has _____ neutrons.
Chemistry
1 answer:
babymother [125]3 years ago
3 0

Answer: 4 valence electrons, Silicon, Si, 14, 28.0855, 14

Explanation:

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Need asap thank you
cupoosta [38]

Answer:

c.boron-11

Explanation:

The atomic mass of boron is 10.81 u.

And 10.81 u is a lot closer to 11u than it is to 10u, so there must be more of boron-11.

To convince you fully, we can also do a simple calculation to find the exact proportion of boron-11 using the following formula:

(10u)(x)+(11u)(1−x)100%=10.81u

Where u is the unit for atomic mass and x is the proportion of boron-10 out of the total boron abundance which is 100%.

Solving for x we get:

11u−ux=10.81u

0.19u=ux

x=0.19

1−x=0.81

And thus the abundance of boron-11 is roughly 81%.

6 0
2 years ago
Balance the following equations:
lesya [120]
<h2>Hey There!</h2><h2>_____________________________________</h2><h2>Answer:</h2><h2>_____________________________________</h2>

(I) N_{2} + 3H_{2} --> 2NH_{3}

(II) P_{4}  + 5O_{2}  --> 2P_{2} O_{5}

(III) 2NaF + Br_{2}  -->2NaBr + F_{2}

(IV) 2ZnS + 3O_{2} --> 2ZnO + 2SO_2

(V) Pb(NO_3)_2 + 2NaCl --> 2NaNO_3 + PbCl_2

<h2>_____________________________________</h2><h2>Best Regards,</h2><h2>'Borz'</h2>

7 0
3 years ago
Calculate the [H3O+] of solutions a and b; calculate the [OH-] solutions c and d.
patriot [66]

Answer:

I got the answers but it won't let me post it correctly on here....

Explanation:

9.) 10-2.76 =0.0174 [H30+]= 1.74*10-3 M

10.)10-3.65=0.00224  [H3O+] =2.24*10-2 M

11.)10-3.65=0.00224 [OH-]= 2.224*10-4M

12.)10-6.87=0.00000135  [OH-]= 1.35*10-7M

3 0
3 years ago
When energy in the atom is released, what occurs?
sineoko [7]

Answer:

What happens when electrons in atoms absorb or release energy? When electrons absorb or release energy, their electrons can move to higher or lower energy levels. These electrons lose energy by emitting light when they return to lower energy levels.

Explanation:

i really hope this helps

4 0
4 years ago
4.7C Renewable and Nonrenewable Resources
ki77a [65]
Answer: petroleum
because it is a fossil fuel like coal, and natural gas.
4 0
3 years ago
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