Which element has 2 valence electrons in the 2s sublevel?

Answers

Answer 1

Answer:

beryllium is the answer.

I hope this will help you


Related Questions

A pupil has drawn the electronic structure of fluorine and the diagram is shown below. However,
mistakes have been made. State three mistakes that have been made.

Fl atomic number: 9
Fl atomic mass: 10

(ps i have two of these but can’t figure out the last)

Answers

Answer:

The number of electrons in the orbit is wrong they have to be 9 and not 10since flourine is in group 7 the number of electrons in the outer most shell has to be 7 and not 2the first shell has 8 instead of 2 electrons

I hope this helps

What is the name of the molecule shown below?

A) ethanol
B) ethanal
C) ethanoic acid
D) ethylamine

Answers

The answer is B, Ethanal

The name of the molecule shown is Ethanol.

What is Ethanol?

Ethanol is a alcoholic substance that is formed from fermentation of glucose in the presence of yeast or microorganisms.

It has a chemical group that have methyl group, hydroxyl group OH which is bonded to carbon atom.

Therefore, The name of the molecule shown is Ethanol.

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BJECTIVE TYPE QUESTIONS
Fill in the blank spaces by choosing the correct words from the words given in list.
List : composition, heat, chemical, photosynthesis, physical
1. Heating of zinc oxide is a
change.
2. Burning of coal is a
change.
3. There is a change in state and
during a chemical change.
4. Plants make their food by the process of
5.
energy is generally given out or absorbed during a chemical change​

Answers

Answer:

1.Physical change

2. Chemical change

3. Heat

4.photosynthesis

5. composition

Is FeS iron (ll) sulfide or iron (lll) sulfide?

Answers

Answer:

the valence of S is -2. For FeS to be neutral the valence of Fe used must be +2

and since Iron (II) has its valency 2, FeS will be Iron (II) Sulfide.

Element 'X' forms a chloride with the formula XCl2, which is a solid with high melting point. X would most likely be in the same group of the periodic table as:

I) Si
2) Al
3) Mg
4) Na



pls pls answer fast ​

Answers

Answer:

Mg

Explanation:

Mg forms 2+ ions and mgcl2 has a melting point over 700°C I believe.

Help me please

The options are
A. Translation
B. Rotation
C. Enlargement
D.reduction

Answers

this is enlargement since the new image has been enlarged twice the size of the original.

translation means it has moved
rotation means it turned another way
reduction means it got smaller

Answer:

C. Enlargement

Explanation:

True or false, The universal gas constant, R, is . 0821 when we use mm Hg as our unit for pressure

Answers

Answer:

False

Explanation:

R = gas constant = 0.0821 atm•L/mol•K

CH3 CH2 CH2 OH + H2SO4
Get the product and answer the following questions :

I. A + HCl
II. A --> Combustion ( what product does it form. Write out the equation )
III.A ---> Hydrogenation (what product does it form. Write out the equation )



Note : A represents the product gotten from the reaction between
CH3 CH2 CH2 OH and H2SO4​

Answers

Answer:

propene and hydrogen is product

When propanol is heated with concentrated sulphuric acid at 443 K, dehydration takes place and prop-1-ene is formed. In this reaction concentrated sulphuric acid acts as a dehydrating agent.

I. A + HCl gives )-gives 2-chloropropane

II. A --> Combustion ( what product does it form. Write out the equation propene ozonide

III.A ---> Hydrogenation (what product does it form. Write out the equation )propanol

2. Nitric oxide contains 46.66% nitrogen and 53.34% oxygen. Water contains 11.21% hydrogen and 88.79% oxygen. Ammonia contains 17.78% hydroger and 82.22% nitrogen. Use these data to verify the law of reciprocal proportions. ​

Answers

Answer:

The law of reciprocal proportions states that if two elements react individually with a given weight of a third element, the ratio of the masses with which they combine with the third element are either the same or a simple multiple of the ratio of the masses with which they combine with each other

The compounds formed includes;

1) Nitric oxide, NO

Nitrogen = 46.66% × 30.01 = 14

Oxygen = 53.34% × 30.01 = 16

2) Water, H₂O

Hydrogen = 11.21% × 18.01528 = 2

Oxygen = 88.79% × 18.01528 ≈ 16

3) Ammonia, NH₃

Hydrogen = 17.78% × 17.031 ≈ 3

Nitrogen = 82.22% × 17.031 ≈ 14

The ratio of nitrogen to oxygen in nitric oxide = 14:16 = 7:8

The ratio of nitrogen to hydrogen in ammonia = 14:3

The ratio in which hydrogen and oxygen combine with nitrogen = 3/16

The ratio of hydrogen and oxygen combine with each other in water = 2/16

Therefore, the ratio with which hydrogen and oxygen combine with nitrogen, is (2/3) times the ratio with which they combine with each other, which verifies the law of reciprocal proportions

Explanation:

Plants in forests take up carbon dioxide from the atmosphere during photosynthesis. They transform the carbon dioxide into plant material. When plants die, their organic matter is often worked into the soil by decomposers. Some of this organic matter remains within the soil and forest floor, and some of it is taken up by other living things.

Based on this information, what role do forests play in the carbon cycle?
A.
Forests are carbon sinks because they store carbon.
B.
Forests are carbon sinks because they do not absorb carbon dioxide when plants die.
C.
Forests are carbon sources because they emit carbon.
D.
Forests are carbon sources because they can be burned to emit carbon dioxide.

Answers

Answer is A

Because Trees store carbon and make it oxygen

Answer: B. forests are carbon sinks because they store carbon

Explanation:forests take up carbon from the atmosphere through photosynthesis and from organic matter through decomposition. so, forests are carbon sinks because they store carbon

I need help with question 5

Answers

Answer:

B a spring being stretched

Sodium and chlorine combine to form table salt.
2Na(s) + Cl2(g) → 2NaCl(s)
Does this reaction obey the law of conservation of mass?

Answers

Answer:

yes it does

Explanation:

because the ratios on the reactants and products are equal

The reaction 2Na(s) + Cl₂(g) → 2NaCl(s) obeys the law of conservation of mass.

Yes, this reaction obeys the law of conservation of mass. The law of conservation of mass states that mass is neither created nor destroyed in a chemical reaction; it is only rearranged.

In the given reaction, we have 2 sodium atoms (Na) on the left side and 2 sodium atoms (Na) on the right side. Similarly, we have 2 chlorine molecules (Cl₂) on the left side and 2 chlorine atoms (Cl) on the right side. Therefore, the number of atoms of each element is balanced on both sides of the reaction.

Additionally, the total mass of the reactants (2Na + Cl₂) is equal to the total mass of the product (2NaCl). The coefficients in the balanced equation represent the stoichiometric ratios, ensuring that the mass is conserved.

Hence, the reaction 2Na(s) + Cl₂(g) → 2NaCl(s) obeys the law of conservation of mass.

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the text of oxygen gas in the laboratory ​

Answers

Explanation:in testing for oxygen a glowing splint is used.

the glowing splint is brought in the presence of the test tube containing the gas

the glowing splint rekindles or lights up showing that oxygen is present.

this is a positive test because oxygen supports burning or combustion

Describe weighted average

Answers

Answer:

Explained below

Explanation:

In simple average, we just add all the given data variables and divide it by the number of data given.

However, when it comes to weighted average, what we do is that we multiply each given variable by their weights and then divide the sum of that by the sum of the weights.

Thus, if the variables are denoted by x and their weights are denoted by y, then we have;

Weighted average = Σ(xy)/Σy

Analysis of an ore of calcium shows that it contains 13.61 g calcium and 21.77 g oxygen in a 46.28-g sample. Calculate the percent composition of this compound.

Answers

Answer:

29.41% of Calcium and 47.04% of Oxygen

Explanation:

The percent composition of an atom in a molecule is defined as 100 times the ratio between the mass of the atom and the mass of the molecule.

The mass of the molecule of the problem (Ore) is 46.28g. That means the percent composition of Calcium is:

13.61g / 46.28g * 100 = 29.41% of Calcium

And percent composition of Oxygen is:

21.77g / 46.28g * 100 = 47.04% of Oxygen

Over a period of 2 minutes, 180 coulombs of charge pass through a resistor. What is the current through the resistor during this time?
Type the correct answer in the box. Use numerals instead of words.
The current through the resistor during this time is

A.

Answers

Answer:

Explanation:

Formula

The current = charge / time

The charge is in coulombs

The time has to be in seconds.

1 minute = 60 seconds

2 minutes = 120 seconds.

charge = 180 coulombs

current = 180 / 120

current = 1.5 amperes.

how do i calculate the concentration of a certain solution​

Answers

Answer:

Divide the mass of the solute by the total volume of the solution. Write out the equation C = m/V, where m is the mass of the solute and V is the total volume of the solution. Plug in the values you found for the mass and volume, and divide them to find the concentration of your solution.

For a reaction: aA → Products, [A]o -4.3 M, and the first two half-lives are 56 and 28 minutes, respectively. Calculate k (without units). Show Work!

A. 7.7 x 10^-2
B. 4.2 x 10^-3
C. 3.8 x 10^-2
D. 8.3 x 10^-3
E. None of these​

Answers

Answer:

C.[tex]3.8\times 10^{-2}[/tex]

Explanation:

We are given that

Initial concentration, [tex][A]_o=4.3 M[/tex]

First half life, [tex]t_{\frac{1}{2}}=56[/tex]minutes

Second half life, [tex]t'_{\frac{1}{2}}=28[/tex]minutes

We have to find K.

The given reaction is zero order reaction.

We know that for zero order reaction

[tex]t_{\frac{1}{2}}=\frac{[A]_o}{2k}[/tex]

Using the formula

[tex]56=\frac{4.3}{2k}[/tex]

[tex]k=\frac{4.3}{2\times 56}[/tex]

[tex]k=3.8\times 10^{-2}[/tex]

Hence, option C is correct.

Zero-order reactions are the reactions when a surface or a catalyst is required for the reaction to proceed and is saturated by the reactant chemicals. The result of the concentration versus the time plot will be a straight line in a zero-order reaction.

[tex]3.8 \times 10 ^{-2}[/tex] is the value of k.

How to calculate the value of k?

Given,

Initial concentration [tex][A_{0}][/tex] = 4.3 MThe first half-life of the reactant [tex](t \dfrac{1}{2})[/tex] = 56 minutesThe second half-life of the reactant [tex](t \dfrac{1}{2})[/tex]  = 28 minutes

The given reaction in the question is of zero-order and for that, we know that,

[tex]t \dfrac{1}{2} = \dfrac{[A_{0}] }{2\;\rm k}[/tex]

Substituting the values in the equation we get:

[tex]\begin{aligned}56 &= \dfrac{4.3 }{2\; \rm k}\\\\\rm k &= {4.3 }{2 \times 56}\\\\\rm k &= 3.8 \times 10^{ -2}\end{aligned}[/tex]

Therefore, option C is correct.

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Which is a mixture?
Sodium metal
chlonne gas
sodium metal and chlonne gas
sodium chlonde (salt) and water

Answers

Answer:

I believe it's salt and water

Explanation:

not sure

Answer:

Mixture is a electronic device used to peel the things such as onion ,tomato,ginger, garlic etc.

The intermediate product formed during the production of urea is,

Answers

Answer:

Arginine is intermediate product formed during the production of urea

The key combination is ornithine, on which the urea molecule is 'created'; intermediates in the procedure contain citrulline and arginine.

What is the Production of Urea?

The urea cycle is a procedure of conversion of toxic ammonia to negligibly toxic urea. Consequences of the urea cycle are 1 molecule of urea, 2 molecules of ADP, and 1 molecule of both AMP and fumaric acid.

When Ammonia and carbon dioxide recovery During urea decomposition a mixture of gaseous carbon dioxide and also ammonia is accumulated and also immersed into a dilute aqueous urea resolution.

Find more information about Production of Urea here:

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when carbon is heated in a limited supply of oxygen, a gas is obtained.
1 .what is the name of this gas​

Answers

Answer:

carbon monoxide

I think its correct but I am not sure

Answer: when carbon is heated in air carbon dioxide is formed, so is incomplete combustion which results in carbon monoxide.

Explanation: but when carbon dioxide reacts with more oxygen carbon monoxide is formed i guess.

I AM A BIT SURE BUT HOPE THIS HELPSSSS!!!!

What is the percent yield of a reaction?
O A. The difference between measured and calculated amounts
OB.
The amount of produd obtained
amount possible
* 100
C. The amount of product actually obtained in a reaction
D. The amount of product that is possible from a reaction

Answers

Answer:

B. The amount of produd obtained/amount possible * 100

Explanation:

In chemistry, the yield of a chemical reaction is the quantity or amount of products obtained in that chemical reaction. It is calculated by using the following formula:

Percentage yield = Actual yield/theoretical yield × 100

- The actual yield is the amount of products got from a chemical reaction

- The theoretical yield is the amount of product got from using the balanced equation (stoichiometry).

______ exhibits the highest
intermolecular forces of the states of matter.

A. Solid

B. Liquid

C. Gas

D. Vacuum

Answers

I would say A) solid

To begin the experiment, Xavier washed his hands and put on safety goggles. He then measured 120 milliliters of tap water, 2.5 milliliters of baking soda, and 2.5 milliliters of citric acid. The initial temperature of the water was 23.5°C.


Next Xavier added the baking soda and citric acid to the water. The mixture immediately began to bubble vigorously, which lasted for about 30 seconds. The new temperature of the mixture was 17.7°C.

Is a chemical reaction taking place during Xavier’s experiment? How do you know?



WILL GIVE BRAINLIEST!!!!!!!!!!!!!!!

Answers

Answer:

Yes a chemical reaction is taking place.

Explanation:

There is a change in temperature along with bubbling. All signs of a chemical reaction.

Yes a chemical reaction is taking place. Temperature changes are signs of chemical reactions. Bubbling also shows chemical reactions as new substances are being created.

How many atoms of hydrogen are there in 36 g of NH4?

Answers

Answer:

hope it helps you

Explanation:

please like and mark me brainlist

The formula mass of ammonia is 14 + 1 3 = 17. The number of moles in 36 g ammonia is 36/ 17 = 2.11mol. A mole is 6.02 10, so the number of hydrogen atoms in a 2.11 moles of ammonia is 2.11 *6.02*10^23 = 1.27 *10^24 atoms .


Hope it helps!

Name five metal which are both dilute and memorable? class 10​

Answers

Iron, magnesium, zinc, aluminum. I don’t know of any others

what is the molarity of HCL solution that has a density of 1.17g/ml at 25°?​

Answers

~Solution :-

Here, we have been given that;

$ \bf{1 ml}$ = 1.17 g$ \bf{1 l}$ = 1170 g

Hence, we can note that,

No. of moles of HCL (n) = $ \sf{\frac{1170}{36.5}}$

(n) = 32.05

[tex] \\ [/tex]

Thus,

Molarity = 32.05 mg/L

Hence, molarity of the given solution will be 32.05 mg/L.

When it’s summer in the northern hemisphere what Season is it in the Southern Hemisphere

Answers

Answer:

Winter

Explanation:

I dont know but whatev

Answer:

Winter

Explanation:

The seasonal cycle in the polar and temperate zones of one hemisphere is opposite to that of the other. Therefore, When it is summer in the Northern Hemisphere, it is winter in the Southern, and vice versa.

hope it helps :)

mendeleev's periodic table is studied even though it is considered to be defective​

Answers

Answer:

This is because Mendeleev arranged the elements in order of increasing relative atomic mass.

Explanation:

Dmitri Mendeleev is one of the scientists that contributed to the development of periodic table in chemistry. He was able to organise elements into rows according to their atomic mass and into columns based on chemical and physical properties. This is the main reason why his periodic table is still studied even though it has some defects which include:

--> Grouping of elements that are not similar chemically: For example Copper and Silver bear no resemblance with the alkali metals, but they have been placed together in the first group.

--> Position of isotopes: According to his periodic table: Isotopes of an element must be given separate places in the periodic table because they have different atomic masses.

--> Electronic arrangement of elements: It failed to explain the electronic arrangement of elements.

--> Separation of chemically similar elements:

Elements that are chemically similar such as Gold and Platinum have been placed in separate groups.

Hiii pls help me to write out the ionic equation ​

Answers

Answer:

STEP I

This is the balanced equation for the given reaction:-

[tex] 2KOH_{(aq)} + H_2SO_4{}_{(aq)} \rightarrow K_2SO_4{}_{(aq)} + 2H_2O_{(l)} [/tex]

STEP II

The compounds marked with (aq) are soluble ionic compounds. They must be

broken into their respective ions.

see, in the equation KOH, H2SO4, and K2SO4 are marked with (aq).

On breaking them into their respective ions :-

2KOH -> 2K+ + 2OH-H2SO4 -> 2H+ + (SO4)2-K2SO4 -> 2K+ + (SO4)2-

STEP III

Rewriting these in the form of equation

[tex] \underline{\pmb{2K^+} }+ 2OH^- + 2H^+ + \pmb{\underline{{SO_4{}^{2-}}} \: \rightarrow \: \underline{\pmb{2K^+}}} + \underline{\pmb{SO_4{}^{2-}}} + 2H_2O [/tex]

STEP IV

Canceling spectator ions, the ions that appear the same on either side of the equation

(note: in the above step the ions in bold have gotten canceled.)

[tex] \boxed{ \mathfrak{ \red{ 2OH^-{}_{(aq)} + 2H^+{(aq.)} \rightarrow H_2O{}_{(l)}}}} [/tex]

This is the net ionic equation.

____________________________

[tex] \\ [/tex]

[tex]\mathfrak{\underline{\green{ Why\: KOH \:has\: been\: taken\: as\: aqueous ?}}} [/tex]

KOH has been taken as aqueous because the question informs us that we have a solution of KOH. by solution it means that KOH has been dissolved in water before use.

[Alkali metal hydroxides are the only halides soluble in water ]

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