what are the elements in the first period

Answers

Answer 1

Answer:

Explanation:

There are only two elements in the first period: hydrogen and helium. We can explain why there is less elements in the first row in modern theories of atomic structure.

Answer 2

Answer:

"Hydrogen and Helium". Hydrogen and Helium are the elements of the first period in the modern periodic table.

Explanation:


Related Questions

what is the percent of aluminum found in Al2SO4

Answers

Answer:

15.772%

Explanation:

2 Write a word equation and
a symbol equation for the
reaction of solid zinc oxide
(ZnO) with sulfuric acid.

Answers

Answer:

Zinc oxide is react with sulphuric acid to give zinc sulphate and water.

zinc oxide +sulphuric acid ⇒ zinc sulphate + water

Zno    +H2So4 ⇒ZnSo4 + H2O

SULPHURIC ACID = H2SO4

ZINC SULPHATE =ZnO

Explanation:

How many molecules are in 7V205?​

Answers

Answer:

Calculate the number of moles you have by taking the Mass / molar mass. if you have 1000 grams ; then 1,000 g / 151.001 g/mol = X g moles. Then multiply by Avogadros # = 6.022140857 × 10^23 molecules per g mole. The result is the # of molecules of MnSO4

Explanation: Hope this helps

Lions eat antelopes. Antelopes eat plants.
A lion is eating an antelope.
Which of these statements correctly describes what is happening when a lion eats an antelope?
A carnivore is eating its prey
B herbivore is eating its prey
C predator is eating a carnivore
D prey is eating a herbivore

Answers

Answer:

A

Explanation:

lions only eat meat, antelopes are prey

A, carnivore is eating its prey

How many valence electrons does the following element have? 1s2 2s2 2p6 3s1

Answers

It’s sodium and it has one valence electron.

What is the temperature in kelvin of a gas if it is allowed to expand from 1.50 L to 4.50 L? The initial temperature is 10.0°C and pressure is constant throughout the change.
Which equation should you use?

StartFraction V subscript 1 over T subscript 1 EndFraction equals StartFraction V subscript 2 over T subscript 2 EndFraction.

T subscript 2 equals StartFraction V subscript 1 over V subscript 2 EndFraction T subscript 1.

T subscript 2 equals StartFraction V subscript 2 over V subscript 1 EndFraction T subscript 1.

Answers

Answer:

first question is the third option and the second question is 849K.

Explanation:

Answer:

third option

849K

Explanation:

word equations- Please help ASAP

Answers

Answer:

See answer below

Explanation:

In this case, you just need to use any acid you want (Like HCl, or H₂SO₄) to do this exercise.

You are given a sample of what you have to do which is:

Acid + metal ------> Salt + hydrogen

As you can see, an acid like the ones I wrote above, have hydrogen atoms, so you should put the hydrogen there. As for the part of salt, you just need to draw the corresponding salt that is formed when the acid reacts with the metal, and write it's name.

Let's do all three equations for you to a better understanding. For all the given examples, I will use HCl as acid, and i will explain one reaction cause the other two reactions happens the same thing, only with a different metal.

1. 2HCl + Zn ------> ZnCl₂ + H₂

As you can see, we just have a displacement reaction where the metal displaces the position of the hydrogen to form the salt and the hydrogen leaves the molecule as a gaseous molecule. Written in words it would be:

Hydrochloric acid + Zinc ----> Zinc chloride + hydrogen

2. 2HCl + Pb -------> PbCl₂ + H₂

Hydrochloric acid + lead ------> Lead (II) chloride + hydrogen

3. 2HCl + Fe -------> FeCl₂ + H₂

Hydrochloric acid + iron ------> Iron (II) chloride + hydrogen

Hope this helps

Compound X has a molar mass of 104.01·gmol−1 and the following composition: element mass % nitrogen 26.93% fluorine 73.07% Write the molecular formula of X .

Answers

Answer: N2F4

Explanation:(NF2)x2 = N2F2

The compound X has a molar mass of 104.01·gmol−1 and the following composition: element mass % nitrogen 26.93% fluorine 73.07%, then the molecular formula of X is N2F4.

What is molecular formula?

Molecular formula is defined as a chemical formula that give the total number of atoms of each elements in each molecule of a substance.

It can also be defined as a phrase that specifies the number of atoms of each element in a complex molecule.

It represents the actual number of each atom in a molecules.

It tells us which atoms and how many of each types of atoms are present in a molecule.

NF2 x 2 = N2F4

Thus, the compound X has a molar mass of 104.01·gmol−1 and the following composition: element mass % nitrogen 26.93% fluorine 73.07%, then the molecular formula of X is N2F4.

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Can you divide equation II by another factor and still have it be correct? Why or why not?

Answers

Answer:

No. You can not simplify a coefficient of.

Explanation:

:)

NaCl + NH3 + CO2 + H20 NaHCO3 + NH4CI
Which Lewis electron-dot diagram correctly represents the reactant containing nitrogen in the equation?

Answers

Since its asking for just the reactant, you can ignore the whole left side. Now since its only asking for the reactant containing Nitrogen, you can ignore the NaHCO3 since it doesnt have nitrogen.
That leaves us with drawing the structure of NH4Cl.
This was a tough one for me to find, as I kept drawing Ammonia instead and couldnt figure out how to fit in the extra Hydrogen and Chlorine. Luckily, this Y!A answer explains it, its due to a hydrogen bond

Option (1) represents the Lewis electron-dot diagram correctly containing nitrogen in the equation.

Lewis Structure is a very simplified representation of the valence shell electrons in a molecule.  It is used to show how the electrons are arranged around individual atoms in a molecule. Electrons are shown as "dots" or for bonding electrons as a line between the two atoms.

Valence electrons are given by hydrogen atoms = [tex]1\times3=3[/tex]

Valence electrons are given by nitrogen atom = [tex]5\times1=5[/tex]

Total valence electrons = 3 + 5 = 8

So, the calculation above is shown only the first option. So, (1) Lewis electron-dot diagram correctly represents the reactant containing nitrogen in the equation.

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Select the correct answer.

Copper carbonate (CuCO3) reacts with hydrochloric acid (HCl) according to this equation:
CuCO3(s) + 2HCl(aq) → CuCl2(aq) + H2O(l) + CO2(g).

Which statement correctly describes the substances in this reaction?

A.
Exactly one product and two reactants are either liquid or dissolved in water.
B.
Exactly one of the reactants is in a water-based solution, but none of the products are.
C.
The reactants include both a liquid and a gas.
D.
Exactly one reactant is a solid, and exactly one product is a gas.
E.
The products include a solid, a liquid, and a gas.

Answers

Answer:

I think the answer would be option d.

hope it helps.

what is haemoglobin? Name its function.​

Answers

Answer:

Haemoglobin is the red pigment which is present in our blood and helps in transporting oxygen to different parts of our body.

Hope it helps

Answer:

Haemeglobin is a red substance that has the function of transporting oxygen into the blood.

Explanation:

what is the mass of 0.75 mol of hydrogen sulfide

Answers

Answer:

25.56066

Explanation:

hope this helps !!!!!!! and sorry if it doesn't help

The answer is deffo 25.56066

the more massive an object is, the more

Answers

Answer:

it have more more mass, gravitational potential energy

Explanation:

It will have more mass and gravitational pull

15) When dilute sulfuric acid is added to zinc metal the products of the reaction are

A zinc oxide + water + hydrogen

B zinc oxide + hydrogen

C zinc sulfate + water + hydrogen

D zinc sulfate + hydrogen

Answers

The answer is D - zinc sulphate and hydrogen

balance the following equation FeC²+Cl². FeCl³​

Answers

Answer:

this equation is not proper see that where is the reactant.

Explanation:

give give a proper question and I will

if fecl2 + c2 gives a fecl3 where does the carbon compound go

Answer:

2FeCl2 + Cl2 → 2FeCl3

Explanation:

what's the difference between viscosity and flow rate

Answers

Answer:

Flow rate is how fast a fluid moves. The flow rate can depend on several factors. These factors are the type of fluid that you are using, the force that is pushing on a fluid, the size of the pipe the fluid flows from and the type of surface the fluid flows over. Viscosity is the resistance of a fluid to flow.

Explanation:

just looked it up

How can you tell, from the drawings, that gravity is greater on Earth
than on Venus?

‼️ Physics‼️

Answers

Answer:

hi basically also also Aussie

Help plz pozlzlzksj help

Answers

Answer:

increase moles of gas inside

Explanation:

Answer:

Its ( C )- Decrease the temperature of the gas inside the basketball

Explanation:

To make sure the balloon doesn't inflate so much it bursts you should NOT completely inflate the balloons when you know the temperature will increase!

the atoms in the same period on the periodic table all have what ?
A - The same abbreviation
B - The same number of electron shells
C - the same number of electrons
D - the same number of electrons on the outer energy level

Answers

Answer:

B.

Explanation:

A period in the periodic table is a row of chemical elements. All elements in a row have the same number of electron shells. Each next element in a period has one more proton and is less metallic than its predecessor.

I also think the answers is B have a beautiful day:)

Molar Concentration of H2O+ lons
in Four Solutions
Solution Molar Concentration
of H3O+ lon
(M)
A 0.1
B 0.01
с 0.001
D I’m 0.0001
Which solution has the highest pH?

Answers

Answer:

d

Explanation:

because it’s moving the most spots to the left

The acidity or alkalinity of a solution depends upon its hydronium ion concentration and hydroxide ion concentration. Here among the given solutions, the solution D has the highest pH. The correct option is D.

What is pH?

The pH of a solution is defined as the negative logarithm to the base 10 of the value of the hydronium ion concentration in moles per litre. The pH scale is introduced by the scientist Sorensen. It is more easy to express the concentration of H₃O⁺ using this method.

The equation used to calculate the pH of the solution is given as:

pH = -log[H₃O⁺]

For 0.1 M

pH = -log[0.1] = 1

For 0.01 M

pH = -log[0.01] = 2

For 0.001 M

pH =  -log[0.001] = 3

For 0.0001 M

pH =  -log[0.0001] = 4

So solution D has the highest pH which is 4.

Thus the correct option is D.

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Gold has a molar mass of 197.0 g/mol. What is the concentration of gold in seawater in moles per liter?(please show work)

Answers

Answer:

Since you didnt get asked for a spefic weight of gold lets assume it was 5g

Explanation:

5g Au/197 =.02538 mols in 1 liter of sea water is

.02538/1L which gives you a Molarity of .012538 assuming 5g if they ask for a different number just replace 5 with any weight in grams

What colour change would you notice with China rose indicator when you add it to soap water and vinegar?

Answers

Dark Pink is observed.... When both are mixed....

HCO3− + H2S → H2CO3 + HS−
In the reaction above, what is the Bronsted-Lowry acid?

Answers

Answer:

H₂S is the proton donor => Bronsted Acid

Explanation:

according to periodic trends which element would have more valence electrons than sulfur

Answers

Answer:

Chlorine,Argon

Explanation:

All the elements of group 18 and group 17

The periodic table depicts the various elements arranged based on the increasing order of their atomic numbers. Argon and chlorine will have more valence electrons than sulfur.

What is the periodic trend of valence electrons?

A valence electron is an electron of an atom present in the outermost shell that participates in bond formation. The valence electrons are the same in elements placed in the same group or family.

The number of valence electrons increases in a horizontal row called the period of the periodic table. As when one moves from left to right in a period the valence electron increases.

The number of valence electrons in a sulfur atom is 6, whereas in chlorine is 7 and in argon is 8. As chlorine and argon are placed after sulfur in a period will have more valence electrons.

Therefore, argon and chlorine have more valence electron than sulfur.

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what is condensation transfer of energy?

Answers

Answer:

Condensation happens when molecules in a gas cool down. As the molecules lose heat, they lose energy and slow down. They move closer to other gas molecules. Finally these molecules collect together to form a liquid.

Hopefully this helped :)

How can a paperclip float on water? Use the
word 'surface tension' in your answer,

Answers

It seems to defy the laws of physics, but a paper clip made of steel can indeed float on the water surface. The high surface tension helps the paper clip - with much higher density - float on the water.

1. MnO₂ is an example of what type of bond?

a covalent
b ionic
c polyatomic ion

2. Cl is an example of a cation, anion, or polyatomic ion

a polyatomic ion
b anion
c cation

Answers

Answer:

1. covalent

2. polyatomic ion

Explanation:

:)

Answer:

1) b

2)c

Explanation:

when combined the two substances together in the cup, the product can be described as a ____ or ____ (there are two possible answers . you just need to choose one )
1. white gas
2. white liquid
3. white solid

Answers

I am pretty sure it is white white liquid but if I’m not right I am so sorry

which alkaline earth metal is the components of quick lime​

Answers

Answer:

Calcium

Explanation:

is a silver-gray metal which takes its name from the Latin word calx, which means lime. It is the fifth most abundant element in the earth's crust and is widely distributed as limestone (CaCO3), quicklime (CaO) and calcium fluoride.

Alkaline earth metals are present on the left of the periodic table. Therefore, calcium is the alkaline earth metal is the components of quick lime​.

What is metal ?

Metals are those elements which is hard, conduct electricity, ductile, lustrous and malleable.

The properties of metals are:

1.Since metals have free electrons that's why they can conduct electricity

2. Since atoms in metals are very closely packed in a definite crystal so these are solid. It is not brittle that is it can not be broken down easily

3. It does not react with water easily.

4.It is denser than water hence it sink in water.

The formula for quick lime is quicklime (CaO). The alkaline earth metal that is component of quick lime is calcium Ca. Quick lime is used in white washing.

Therefore, calcium is the alkaline earth metal is the components of quick lime​.

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