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Volgvan
4 years ago
13

(80 POINTS - will mark brainliest)

Chemistry
2 answers:
Otrada [13]4 years ago
5 0
The symbols, Li, Be, B, C, N, O, F, and Ne are all in the same period (row). The periods are numbered from 1 through 7. The symbols Li, Be, B, C, N, O, F, and Ne are all in period 2.
Elements in period 2 all have two energy levels surrounding their nucleus. The period number always equals the number of energy levels that the atoms of an element in that period have.

Hope this helped! Mark me Brianliest please:)
Serjik [45]4 years ago
3 0

The elements Li,  C, and F, are all in the period (row) # 2 of the periodic table, and, in consequence,  those atoms have two energy levels (main quantum number), n = 1 and n = 2, around the nucleus.The period number of an element in the periodic table is always equal to the number of main energy levels that the atoms have.Li (lithium), C (carbon), and F (fluor) form part of the period 2 of the periodic table.The complete  list of elements of the period 2 of the periodic table is  Li, Be, B, C, N, O, F, and Ne.The periods are numbered from 1 through 7.The elements of period 1 (H and He) have one main energy level, the elements in period 2 have two main energy levels, the elements in period 3 (Na, Mg, Al, Si, P, O, Cl, and Ne) have three main energy levels. So, as you can infere, the period number always equals the number of main energy levels of the atoms of the element.

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Can u pls help me with this question ​
muminat

Answer:

it's mass

Explanation:

just trust me it's just mass

3 0
3 years ago
a student is given two 10g samples, each a mixture of only NaCL(s) and KCI(s) but im different proportions. how does knowing the
shepuryov [24]

Answer:

Knowing the mass of chlorine in each mixture will enable you find the empirical formulas that will lead to molecular formulas for the compounds in the mixture.This information will help you determine which mixture has a higher proportion of the compound in question.

Explanation:

In determining the percent composition of a compound in a mixture,mass of a compound will be the first step to be determined.This will then allow you to find mole to mole ratio of all elements in that compound.Having mole ratio information, and mass, it will be possible to find ratio of ions in the compound,and determine the mixture with higher proportion of the compound.

Molecular weight and the empirical formula of the compound will led you to the molecular formula of the compound,that will show you the mole ratios which now you can use to determine proportions of the compound in a mixture.

3 0
3 years ago
Compare a low-dose rate internal radiation treatment to a high dose rate internal treatment. What do you think are the positives
Assoli18 [71]
Internal radiation is also called brachytherapy. A radioactive implant is put inside the body in or near the tumor. Getting the implant placed is usually a painless procedure. Depending on your type of cancer and treatment plan, you might get a temporary or a permanent implant. Internal radiation therapy (brachytherapy) allows a higher dose of radiation in a smaller area than might be possible with external radiation treatment. It uses a radiation source that’s usually sealed in a small holder called an implant. Different types of implants may be called pellets, seeds, ribbons, wires, needles, capsules, balloons, or tubes. No matter which type of implant is used, it is placed in your body, very close to or inside the tumor. This way the radiation harms as few normal cells as possible.

During intracavitary radiation, the radioactive source is placed in a body cavity (space) , such as the rectum or uterus.
With interstitial radiation, the implants are placed in or near the tumor, but not in a body cavity. The implant procedure is usually done in a hospital operating room designed to keep the radiation inside the room. You’ll get anesthesia, which may be either general (where drugs are used to put you into a deep sleep so that you don’t feel pain) or local (where part of your body is numbed).

One or more implants is put into the body cavity or tissue with an applicator, usually a metal tube or a plastic tube called a catheter. Imaging tests (an x-ray, ultrasound, MRI, or CT scan) are usually used during the procedure to find the exact place the implant needs to go.

Before being placed, implants are kept in containers that hold the radiation inside so it can’t affect others. The health professionals handling the implants may wear special gear that protects them from exposure once the implants are taken out of the container. High-dose-rate (HDR) brachytherapy allows a person to be treated for several minutes at a time with a powerful radioactive source that’s put in the applicator. The source is removed after 10 to 20 minutes. This may be repeated twice a day over a few days, or once a day over the course of a few weeks. The radioactive material is not left in your body. The applicator might be left in place between treatments, or it might be put in before each treatment.

People getting HDR sometimes stay in the hospital if it involves multiple day treatments and if the applicator is left in place. There may be special precautions to take after the treatment, so be sure to talk to the cancer care team about this. In this approach, the implant gives off lower doses of radiation over a longer period.

Some implants are left in from 1 to a few days and then removed. You’ll probably have to stay in the hospital, sometimes in a special room, during treatment. For larger implants, you might have to stay in bed and lie still to keep it from moving.

Some smaller implants (such as the seeds or pellets) are left in place and never taken out. Over the course of several weeks they stop giving off radiation. The seeds or pellets are about the size of rice grains and rarely cause problems. If your implants are to be left in, you may be able to go home the same day they’re put in. There may be special precautions to take, so be sure to talk to the cancer care team about this.




4 0
3 years ago
A mixture of helium, neon, and xenon gases is made with the same mass of each gas. Which (if any) gas will have the highest part
Darya [45]

Answer:

Xe will have the highest partial pressure

Explanation:

Using Dalton's law of partial pressures for ideal gases

p=P*x

where

p= partial pressure , P= total pressure and x = mole fraction = n / ∑n

since the number of moles is related with mass through

n= m/M

where

m= mass and M= molecular weight

then if m is the same for all the gases

x = m*M/ ∑ (m*M) = m*M/ m∑ M  = M/∑ M

thus

p=P*x = P*M/ ∑ M

for the 3 gases

p₁=P*x₁ = P*M₁/ (M₁+M₂+M₃)

p₂=P*x₃ = P*M₂/ (M₁+M₂+M₃)

p₂=P*x₃ = P*M₃/ (M₁+M₂+M₃)

then for gasses under the same pressure (P=constant) and same mass (m=constant) , p is higher when the molecular weight is higher . Therefore Xe will have the highest partial pressure

5 0
4 years ago
Read 2 more answers
Why don’t vegetable oil and water mix?
alexdok [17]

Answer:

Because oil is less dense than water, it will always float on top of water, creating a surface layer of oil.

Explanation:

5 0
4 years ago
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