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Lelechka [254]
3 years ago
5

The total number of the elements above with 2 valence electron is ____.

Chemistry
1 answer:
OverLord2011 [107]3 years ago
4 0

Answer:

four elements

Explanation:

He = 1s²

Be = 1s² 2s²

C = 1s² 2s² 2p²

Mg = 1s² 2s² 2p⁶ 3s²

Si = 1s² 2s² 2p⁶ 3s² 3p²

Ca = 1s² 2s² 2p⁶ 3s² 3p⁶ 4s²

Valence electrons are those electrons which are present in outer most electronic shell.

He, Be, Mg, Ca these four elements have 2 valence electrons.

While Si and C have four valance electrons.

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Balance the following equation <br><br><br> _NaOH (aq) + _HNO3 (aq)&gt; _NaNO3 (aq)+ _H2O (1)
Vlada [557]
Its already balanced, no balancing required
6 0
3 years ago
At Jim's auto shop, it takes him minutes to do an oil change and minutes to do a tire change. Let be the number of oil changes h
Juli2301 [7.4K]

Answer:

The total time that Jim needs to change x oil changes and y tire changes is less than 180 min.

The time needed for x oil changes is 12 * x.

The time needed for y tire changes is 18 * y.

The total time is the sum of the above times and needs to be less than 180 that is

12 * x + 18 * y < 180 divide both sides of equation by 6

12/6 * x + 18/6*y < 180/6

2*x + 3*y < 30

2*x < 30 - 3*y divide both sides by 2 to get the inequality for x

x < 30/2 - 3/2*y = 15 - 1.5 y < 15 that is x < = 15

2*x + 3*y < 30

3*y < 30 - 2*x divide both sides by 3 to get the inequality for y

y < 30/3 - 2/3 *x = 10 - 2/3*x < 10 that is y < = 10

Also we can write x + y < x+ 3/2 * y < 15.

Explanation:

Jim's can do not more then 5 oil changes and not more then 10 tire changes or all together she can do not more then 15 total of oil and tire changes.

5 0
3 years ago
What do a mole of magnesium and a mole of iron have in common
lukranit [14]
What they have in common is that they both have the same number of atoms. Hope this helps. :)
7 0
4 years ago
How might the biodiversity of a mowed lawn compare to that of huge weedy field?
Dennis_Churaev [7]

Answer: The mowed lawn is the one from where the grasses are removed by using the machines or tools.

Explanation:

The mowed lawn is expected to have low number of species as the grasses may be few or scanty thus can support the population of few species like insects, mice, birds, and small number of grazing animals. On the other hand the weedy field can be hub of insects, reptiles like snakes, small mammals, and large mammals. Large weed field can provide food, and habitat to the large number of species. This will support the increase in biodiversity as compared to the mowed lawn.

5 0
3 years ago
Two processes of plant reproduction are described below.
Stells [14]

Answer:

Process 1 is pollination and Process 2 is germination

Explanation:

Pollination is the act of transferring pollen grains from the male anther of a flower to the female stigma. The goal of every living organism, including plants, is to create offspring for the next generation. One of the ways that plants can produce offspring is by making seeds.

Germination refers to the process by which an organism grows from a seed or a spore. The most common forms of germination include a seed sprouting to form a seedling and the formation of a sporeling from a spore. Thus, germination occurs primarily in plant and fungal species.

I hope this help :)

good luck

6 0
3 years ago
Read 2 more answers
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