Total number of elements present in the 3rd period is;

Answers

Answer 1

The third period contains eight elements: sodium, magnesium, aluminium, silicon, phosphorus, sulfur, chlorine, and argon.

Related Questions

238 U 92 write the following decay sequence.​

Answers

Answer: The given decay sequence is [tex]^{238}_{92}U \rightarrow ^{234}_{90}Th + ^{4}_{2}He \rightarrow ^{234}_{91}Pa + ^{0}_{-1}\beta[/tex].

Explanation:

An alpha-particle is a helium atom. Hence, when an alpha decay occurs in [tex]^{238}_{92}U[/tex] then the reaction equation is as follows.

[tex]^{238}_{92}U \rightarrow ^{234}_{90}Th + ^{4}_{2}He[/tex]

Now, in sequence the equation for beta decay is as follows.

[tex]^{234}_{90}Th \rightarrow ^{234}_{91}Pa + ^{0}_{-1}\beta[/tex]

Hence, the sequence will be as follows.

[tex]^{238}_{92}U \rightarrow ^{234}_{90}Th + ^{4}_{2}He \rightarrow ^{234}_{91}Pa + ^{0}_{-1}\beta[/tex]

Thus, we can conclude that the given decay sequence is [tex]^{238}_{92}U \rightarrow ^{234}_{90}Th + ^{4}_{2}He \rightarrow ^{234}_{91}Pa + ^{0}_{-1}\beta[/tex].

What type of reaction happens inside a nuclear power plant?
A. A chemical reaction
B. A photoelectric reaction
C. A nuclear chain reaction
D. An acid-base reaction

Answers

Hello the answer is C i hope this helps you

Please help!!!!!!!!!!!!!!!!!!!

Answers

Answer:

Hydrochloric acid + calcium hydroxide = calcium chloride + water

What is the concentration of a solution made by combining 52 grams of NaCH3COO with 150 mL of water?

Answers

Answer: The concentration of a solution made by combining 52 grams of  [tex]NaCH_{3}COO^{-}[/tex] with 150 mL of water is 4.22 M.

Explanation:

Given: Mass = 52 grams

Volume = 150 mL (1 mL = 0.001 L) = 0.150 L

Molarity is the number of moles of a substance present in liter of a solution.

And, moles is the mass of a substance divided by its molar mass.

Hence, moles of [tex]NaCH_{3}COO^{-}[/tex] (molar mass = 82.034 g/mol) is as follows.

[tex]Moles = \frac{mass}{molar mass}\\= \frac{52 g}{82.034 g/mol}\\= 0.633 mol[/tex]

Therefore, concentration of given solution is as follows.

[tex]Molarity = \frac{moles}{Volume(in L)}\\= \frac{0.633 mol}{0.150 L}\\= 4.22 M[/tex]

Thus, we can conclude that the concentration of a solution made by combining 52 grams of  [tex]NaCH_{3}COO^{-}[/tex] with 150 mL of water is 4.22 M.

What unit is used for atomic mass

Answers

Please mark brainliedt

Answer is daltons
Atomic weight is measured in atomic mass units (amu), also called daltons.




Atomic Mass

Masses of individual atoms are very, very small. Using a modern device called a mass spectrometer, it is possible to measure such minuscule masses. An atom of oxygen-16, for example, has a mass of 2.66 × 10 -23 g. While comparisons of masses measured in grams would have some usefulness, it is far more practical to have a system that will allow us to more easily compare relative atomic masses. Scientists decided on using the carbon-12 nuclide as the reference standard by which all other masses would be compared. By definition, one atom of carbon-12 is assigned a mass of 12 atomic mass units (amu). An atomic mass unit is defined as a mass equal to one twelfth the mass of an atom of carbon-12. The mass of any isotope of any element is expressed in relation to the carbon-12 standard. For example, one atom of helium-4 has a mass of 4.0026 amu. An atom of sulfur-32 has a mass of 31.972 amu.

https://courses.lumenlearning.com/cheminter/chapter/atomic-mass-unit/

In relation to the reactants of a chemical reaction, the products are

Answers

Answer:

the products are the substances made after the chemical reaction has happened

Explanation:

Fill in the coefficients that will balance the following reaction:

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I do not see any picture

Why would the electrolysis reaction stop if the battery was removed

Answers

If the battery was removed, the energy produced by the battery would not be able to continue its path along the circuit.

help chemistry pls answer

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2nd option it is a chemical change from heat

Using the following balanced equation, if you had 48 molecules of O2,
how many molecules of SO3 would you produce?
S8 + 12O2 --> 8SO3

Answers

Explanation:

hope this helps u understand:)

Aqueous solutions of a strong acid and a weak acid of equal concentrations are compared. Which of the following statements are true?

I. The strong acid reacts with a metal oxide but the weak acid does not

II. The weak acid is less disassociated than the strong acid

III. The strong acid has a greater conductivity that the weak acid.

Answers

Answer:

 

Explanation:

Evaluate the method of separation to be used.
1. Stones and rice (for cooking)​

Answers

Answer:

hand picking

Explanation:

as stone is bigger in size we can see them with our eyes so we can handpick it

Answer:

The method of hand picking is used to separate undesirable substances such as small pieces of stones from wheat, rice and pulses. The food grains containing small pieces of stones are taken in a flat container. The pieces of stones are picked up from the grains by hands, one by one, and thrown away.23 Oct 2020

What is the SI unit of mass

Answers

Answer:

kg or kilograms

Explanation:

Answer: Kilogram (kg)

Explanation: The SI unit of mass is the kilogram (kg). It is equal to the mass of the international prototype of the kilogram and it is defined as the mass of platinum-iridum (Pt-Ir).

Based on your understanding of how bond types influence a material’s properties, identify each of the following compounds as being made of ionic, covalent, or metallic bonds.
ANSWER
Steel: Metalic
Propane: Covalent
Calcium chloride: ionic
Water: Covalent
Edge 2021

Answers

Answer: The given compounds are identified as being made of ionic, covalent, or metallic bonds:

Steel - Metallic bondsPropane - Covalent bondsCalcium chloride - Ionic bondsWater - Covalent bonds

Explanation:

A bond formed by transfer of electrons from one atom to another is called an ionic bond. An ionic bond is formed between a metal atom and a non-metal atom.

A bond formed by transfer of electrons from one atom to another is called a covalent bond. A covalent bond is formed between two or more non-metal atoms only.

Steel is actually an alloy of carbon and iron where there is less than 2% carbon, 1% manganese and small amounts of silicon, phosphorus, oxygen and sulphur are present.

When atoms of metals are held together then bond formed between these atoms is called metallic bond.

Hence, steel is made of metallic bond.

Chemical formula of propane is [tex]CH_{3}CH_{2}CH_{3}[/tex] as there are only non-metal atoms are present. So, sharing of electrons takes place in such atoms due to which covalent bonding will be there.

Hence, propane is made up of covalent bonds.  

Calcium chloride contains a metal and a non-metal atom. This means that electrons are being transferred from calcium atom to the chlorine atom. Hence, bond present in calcium chloride is ionic bond.

Water has chemical formula [tex]H_{2}O[/tex]. Since, non-metal atoms are present there so sharing of electrons takes place between hydrogen and oxygen atoms. Hence, covalent bond is present in water.

Thus, we can conclude that given compounds are identified as being made of ionic, covalent, or metallic bonds:

Steel - Metallic bondsPropane - Covalent bondsCalcium chloride - Ionic bondsWater - Covalent bonds

Steel: ✔ metallic

Propane: ✔ covalent

Calcium chloride: ✔ ionic

Water: ✔ covalent

Which of the following statements regarding carbon is false? Group of answer choices Carbon has the capacity to form single and double bonds. Carbon has the ability to bond with up to six other atoms. Carbon has a tendency to form covalent bonds. Carbon has the ability to bond together to form extensive branched or unbranched "carbon skeletons."

Answers

Answer: The statement, carbon has the ability to bond with up to six other atoms is false.

Explanation:

Carbon is a group 14 element and it is a non-metal. The atomic number of carbon is 6 and its electronic distribution is 2, 4.

This means that there are 4 valence electrons present in it. Also, in order to attain stability a carbon atom forms only covalent bonds, that is, it shares its valence electrons with its own atoms or atoms of other elements.

Carbon has the capacity to form single and double bonds.

As valency of carbon is four so it can only combine to 4 other atoms vis single bond and it cannot bond with up to six other atoms.

Carbon shows the property of catenation, that is, it forms covalent bonds with its own atoms in a large number. So, carbon has the ability to bond together to form extensive branched or unbranched "carbon skeletons".

Thus, we can conclude that the statement, carbon has the ability to bond with up to six other atoms is false.

. If you have 5.42 x 1024 aluminum atoms, approximately how many moles is that?


Please help me

Answers

Answer:

5.42x10^24 atoms/1 x 1 mole/6.022x10^23

= 9.5 mol

¿Cual es la sustancia que puede causar la muerte? (Estoy poniendo cualquier cosa para registrarme) 3

Answers

Answer:

Veneno.

Explicación:

El veneno es la sustancia que puede causar la muerte porque el veneno destruye las células que entran en contacto con el veneno. Si el veneno causa menos daño por lo que no ocurre la muerte del paciente mientras que por otro lado, si el veneno entra en contacto con los órganos vitales y causa más destrucción, el paciente eventualmente morirá, por lo que podemos decir que las sustancias tóxicas y venenosas causan daño y muerte. de la gente.

the rows from left to right in the periodic table is called what​

Answers

Answer:

The periodic table has rows that go left to right and columns that go up and down, just like any other grid. The rows are referred to as PERIODS, while the columns are referred to as GROUPS.

Explanation:

what is formed when oxyhaemoglobin splits​

Answers

Explanation:

The haem is in turn split into iron , which forms chemical compounds as part of the blood iron pool available for future hemoglobin synthesis...

hope this help !!

An apple has been left out, and it is starting to rot. Which of the following is the best method to slow down the chemical changes that are occurring?

The best method is to keep rinsing the apple with water every hour.
The best method is to keep the apple in a cooler place.
The best method is to put the apple in the sun to warm it up.
The best method is to wrap the apple in plastic.

Answers

It’s B just answered that question correctly

Identify all of the gas law equations that relate to the ideal gas law.

Answers

Answers to the whole page:

**Check for the proof photo at the bottom.**

**Answers are in bold.**

__________________________________________________________

Answers on the left:

Identify all of the gas law equations that relate to the ideal gas law.

3. V₁/T₁=V₂/T₂

4. V₁/n₁=V₂/n₂

5. P₁V₁=P₂V₂

7. P₁/T₁=P₂/T₂

__________________________________________________________

Answers on the right:

A balloon containing 0.0400 mol of a gas with a volume of 500 mL was expanded to 1.00 L.  Answer the questions and round answers to nearest hundredth place.  Which equation should you use to find the amount of gas added?

B. n₂=V₂n₁/V₁

What is the final number of moles?

0.08  mol

__________________________________________________________

Explanation:

The ideal gas law is Boyle's law, Charles's law, Gay-Lussac's law, and Avogadro's law combined into one equation. Avogadro's law is V₁/N₁=V₂/N₂, Charles's law is V₁/T₁=V₂/T₂, Gay-Lussac's law is P₁/T₁=P₂/T₂, and Boyle's law is P₁V₁=P₂V₂.

For the balloon problem, B is the correct answer because we are looking for the final moles of gas added. Answer B gives the equation that equals n₂, n₂ means final number of moles. The problem gives us initial volume (500 mL), final volume (1 L), and initial moles amount (0.04 mol). Plug these numbers into the equation, n₂=V₂n₁/V₁, using consistent units. Note that V₁=initial volume, V₂=final volume, n₁=initial moles, and n₂=final moles

Here's a photo of Edge just incase.

A student wrote a chemical equation as shown.

2H₂S+ 302 H₂O + SO₂

What should the student do to balance the equation?

Answers

Answer: The student must add 2 infront of both [tex]H_2O[/tex] and [tex]SO_2[/tex] to make the equation balanced.

Explanation:

A balanced chemical equation is one where all the individual atoms are equal on both sides of the reaction. It follows the law of conservation of mass.

For the given unbalanced chemical equation:

[tex]2H_2S+3O_2\rightarrow H_2O+SO_2[/tex]

On the reactant side:

Atoms of H = 4

Atoms of S = 2

Atoms of O = 6

On the product side:

Atoms of H = 2

Atoms of S = 1

Atoms of O = 3

To balance the equation, a student must balance the atoms by adding 2 infront of both [tex]H_2O[/tex] and [tex]SO_2[/tex]

For the balanced chemical equation:

[tex]2H_2S+3O_2\rightarrow 2H_2O+2SO_2[/tex]

what are some different natural events and man-made activities that can affect ocean acidification?

Answers

Some man made events are activities that include the burning of fossil fuels, deforestation and vehicle emissions.
Natural events are earthquakes,floods, wildfires

Ocean acidification is the process of decreased pH levels of the oceans. The burning of fossil fuels and industrialization are man-made activities that lead to this process.

What is Ocean acidification?

Ocean acidification is an increased concentration of acidic components of the oceans due to an increase in the carbon dioxide level of the oceans.

Human activities like cutting down a large number of trees, discharging from industrial outlets, and burning fossils like petrol, coal, diesel, etc. are leading to increased acidification of the oceans.

Therefore, natural causes like increased salinity, flood, and earthquake are the reasons for oceanic acidification.

Learn more about ocean acidification here:

https://brainly.com/question/7604502

Consider the redox reaction below talking place in certain electro chemical cell: Cu(s)+cu^2+(aq) -------> Cu^2+(aq) + Cu (s)

Answers

Answer:

cu+2 ------ oxidation whereas Cu ------ reduction.

Explanation:

In the reaction, cu+2 is the place where oxidation occurs because this cupric ion losses electrons  which causes +2 charge on it. we know that oxidation is the loss of electrons and reduction is the gaining of electrons so the Cu is the place or atom at which reduction occurs. Electrochemical cells have two electrodes, which is anode and the cathode. The anode is the electrode where oxidation occurs whereas the cathode is the electrode where reduction takes place.

How many milliliters of 1.5 M H.So, are needed to exactly
neutralize 20. milliliters of a 0.8 M KOH solution?

Answers

Answer: A volume of 10.66 mL of 1.5 M H is required to exactly neutralize 20. milliliters of a 0.8 M KOH solution.

Explanation:

Given: [tex]M_{1}[/tex] = 1.5 M,     [tex]V_{1}[/tex] = ?

[tex]V_{2}[/tex] = 20 mL,         [tex]M_{2}[/tex] = 0.8 M

Formula used to calculate the volume is as follows.

[tex]M_{1}V_{1} = M_{2}V_{2}[/tex]

Substitute the values into above formula as follows.

[tex]M_{1}V_{1} = M_{2}V_{2}\\1.5 M \times V_{1} = 0.8 M \times 20 mL\\V_{1} = 10.66 mL[/tex]

Thus, we can conclude that a volume of 10.66 mL of 1.5 M H is required to exactly neutralize 20. milliliters of a 0.8 M KOH solution.

A compound being used in experimental medicine is 78.14% boron (B) and 21.86% hydrogen (H). The empirical formula of the compound will have a boron to hydrogen ratio of

Answers

Explanation:

hope the picture above help u understand :)

ASAAAP HURRRY PLS!!!
Where in aerobic respiration is the largest amount of energy produced?

A)

At the beginning of the cycle, when glucose is oxidized to pyruvate.

B)

At the end of the electron transport chain, when oxygen is reduced.

C)

At the end of the electron-transport chain, when oxygen is oxidized.

D)

At the beginning of the electron transport chain, when oxygen is oxidized.

Answers

C or D! When reduced coenzymes produce in the process of the cycle, are oxidized in the process of oxidative phosphorylation in electron transport chain! I hope this helps :(
it’s D! at the beginning of the electron transport chain, the oxygen is oxidized.

Example of POTENTIAL ENERGY:

and

Example of KINETIC ENERGY:

Answers

Potential : a yoyo before it’s been released
Kinetic : skateboarding
Rivers are strictly kinetic energy at work. The water is constantly moving, and all that motion is constantly creating kinetic energy.

Rbber bands can be classified as potential depending on the state of the band. When an elastic is stretched, it’s loaded with potential energy

Balance the equation above please ​

Answers

Answer:

Balanced Equation:-

Al2(CO3)3. ---heat---> Al2O3 + 3 CO2

Answer:

everything can be found in the picture

A reaction requires 22.4 L of gas at STP . There are 25.0 L of gas at 101.5 kPa and 373 K.

Which statement is true?

Use the ideal gas law: PV = nRT where R = 8.31 L-kPa/mol-K

A. There is not enough gas for the reaction.

B. Given this information, there is no way to tell if there is enough gas for the reaction.

C. There is excess gas for the reaction.

D. There is enough gas for the reaction.

Answers

Answer:

STP is 101.325 kPa pressure and 273K temperature

Also, at STP, 1 mol of an ideal gas = 22.4 L

Since the question states that 22.4 L are needed at STP, we know that ONE MOLE is needed.  Now, the question is, how many moles are actually present?

V = 25.0 L

P = 101.5 kPa

T = 373K

n = ?

R = 8.31 L-kPa/Kmol

Solving the ideal gas law for n (moles) and comparing that to 1 mole, we have...

n = PV/RT = (101.5)(25.0)/(8.31)(373)

n = 0.82 moles of gas.  THIS IS NOT ENOUGH as it is less than the ONE mole required.

Explanation:

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