how many periods are there in the modern periodic table of elements?​

Answers

Answer 1

Answer:

There are seven periods in the modern periodic table.

Answer 2

Answer:

Seven periods

Explanation:

There are seven periods in the periodic table, with each one beginning at the far left. A new period begins when a new principal energy level begins filling with electrons. Period 1 has only two elements (hydrogen and helium), while periods 2 and 3 have 8 elements.


Related Questions

WILL GIVE BRAINLIEST

Answers

Answer:

b

Explanation:

Which equation is balanced?
A. H 2 + O 2 → H 2O
B. 2Na + Cl 2 → 2NaCl
C. KClO 3 → KCl 2 + 3O 2
D. CH 4 + 2O 2 → CO 2 + H 2 O

Answers

B. is the correct answer

Because in both sides (reactant and product) are:
Na= 2. Na=2
Cl=2 Cl=2

So this equation is balanced

please help i genuinely don’t know what to do

Answers

Like, the first one is
Na ->1
O ->1
H-> 1
Total->3
And so on

Hydrolysis of fructose..​

Answers

Answer:

Fructose, as glucose, reacts in high-temperature and supercritical water to several products. For the hydrolysis of fructose to 5-(hydroxymethyl)-furfural (HMF), Antal and coworkers [6,24] found a sequence of reactions commencing with the fructofuranose ring and retaining it intact.

Explanation:

How to calculate the number of moles

Answers

Answer:

1. The formula for the number of moles formula is expressed as.

2. Given.

3. Number of moles formula is.

4. Number of moles = Mass of substance / Mass of one mole.

5. Number of moles = 95 / 86.94.

PLS HELP ME!!!!!!!!!!!!!! I DON'T HAVE A LOT OF TIME !!!!!!!!

Answers

Answer: Well i think i have saw this i wolud say B hope this helps

Explanation:

How do trends in the periodic table help predict the properties of an element

Answers

as you move around there is a change in: electronegativies, ionisation energies, atomic radius etc. different amounts of these properties are going to effect how the element acts

When the equation
Na +
H2O → __H, +
NaOH
is correctly balanced using the smallest whole-number coefficients, what is the coefficient for H2O?

Answers

The coefficient is 2.
Full equation is
2Na + 2H2O = 2NaOH + H2

The balanced equation is 2Na + 2H[tex]_2[/tex]O [tex]\rightarrow[/tex] 2NaOH + H[tex]_2[/tex] and the coefficient of H[tex]_2[/tex]O is 2. Stoichiometry represents the number of coefficients.

What is balanced equation?

An equation for just a chemical reaction is said to be balanced if both the reactants as well as the products have the same number of atoms and total charge for each component of the reaction. In other words, each sides of both the reaction have an equal balance of mass and charge.

It is typical that balancing chemical formulas for both charge and mass in aqueous solutions. Equal numbers and types of atoms are produced on both aspects of the equation when balancing for mass. When the charge is balanced, there is no net charge on either side of the equation.

The balanced equation can be written as

2Na + 2H[tex]_2[/tex]O = 2NaOH + H[tex]_2[/tex]

The coefficient of H[tex]_2[/tex]O is 2.

Therefore, the balanced equation is 2Na + 2H[tex]_2[/tex]O [tex]\rightarrow[/tex] 2NaOH + H[tex]_2[/tex] and the coefficient of H[tex]_2[/tex]O is 2.

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Mg + Cu2+ —> Mg2+ + Cu

a) why is this a redox reaction?

b) identify the oxidizing agent. Give reason for your answer

answer any of them you want please

Answers

Explanation:

Since the oxidation state of Mg is changed to +2 from 0, it is oxidized. (as it is increased)

Similarly, oxidation state of Cu is changed to 0 from +2, it is reduced. (as it is decreased)

Since oxidation & reduction occur at the same time, it is redox reaction.

As Mg is being oxidized, other one must be the oxidizing agent.

Cu is the oxidizing agent

What gases are exchanged during respiration?

Answers

Answer:

Explanation:

there should be more showing than telling

Answer:

oxygen and carbon dioxide.

Explanation:

HELP!!!!
please omg

Answers

Answer:

I believe it's A. to reduce air bubbles. Tbh, it's been a while

Can someone please help me with the right answer? I only have one more attempt :(

Answers

The decomposition of a solid to yield a gaseous product would involve an increase in entropy. So, the fourth answer choice would be correct.

the equation demonstrates a reaction of sodium chloride and fluorine. 2NaCl+F2=2NaF+Cl2. in order for the reaction to proceed, for every two moles of sodium chloride, there must be at least how many mole(s) for fluorine

Answers

Answer: You would need 1 mole of Fluorine

Explanation:The equation is already balanced so just looking at the coefficients in the equation we can see that Sodium Chloride (2NaCl) needs two moles for this equation and fluorine (F2) only needs one.

In order for the reaction to proceed, for every two moles of sodium chloride, there must be at least  1 mole for fluorine.

Balanced chemical reaction:

2NaCl +  F₂ → 2NaF + Cl₂

The reaction given above is balanced. When 2 moles of sodium chloride reacts with 1 mole of fluorine produces 2 moles of sodium fluoride and 1 molecule of chlorine.

Thus, two moles of sodium chloride, there must be at least  1 mole for fluorine.

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In a molecule of N204 how many different types of atoms are there ?

Answers

Answer:

               Symbol         # Atoms

Nitrogen     N                    2

Oxygen     O                    5

what’s the process of natural selection

Answers

Answer:

Natural selection is the process through which populations of living organisms adapt and change. ... Through this process of natural selection, favorable traits are transmitted through generations. Natural selection can lead to speciation, where one species gives rise to a new and distinctly different species .

Explanation:

i just looked it up lol .

True or false: When adding acid to base the phenolphthalein indicator changes colour from colourless to pink at the end of the titration.

Answers

Answer: false

Explanation: I don’t know why but I just had this question and gussed false and I was right so false is therefore the right answer. Your welcome.

Name three uses for mercury.

Answers

USES OF MERCURY

used in thermometer as it is liquid at room temperature.It is used in batteries , florescent lightit is also used in dental filling

What is the pH of an aqueous solution that has an H+ ion concentration of 0.10 M?
14
10
6
1​

Answers

Answer:

1

Explanation:

pH = -log[H+] = -log(0.10) = log(1.0 x 10^-1) = 1

The pH scale determines how acidic or basic water is. The pH of an aqueous solution that has an H+ ion concentration of 0.10 M is 1. Therefore, option D is correct.

What is pH ?

The pH scale, which previously stood for "potential of hydrogen," is used to describe how acidic or basic an aqueous solution is. The pH values of acidic solutions are typically lower than those of basic or alkaline solutions.

The range is 0 to 14, with 7 representing neutrality. Acidity is indicated by pH values below 7, whereas baseness is shown by pH values above 7. In reality, pH is a measurement of the proportion of free hydrogen and hydroxyl ions in water.

A solution's pH is a significant indicator of its chemical composition. The pH can affect how readily available nutrients are, how biological processes work, how bacteria behave, and how chemicals behave.

pH = -log [ H ⁺ ] = -log ( 0.10 )

= log ( 1.0 x 10⁻¹ )

= 1

Thus, The pH of an aqueous solution that has an H+ ion concentration of 0.10 M is 1. Therefore, option D is correct.

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How is a calorimeter used in this experiment different from the ones used to find the energy content of a snack

Answers

Answer:

Kindly check the explanation section.

Explanation:

PS: Note that enough information are not being provided and we do not know the experiment this question is all about. However, some information are provided below which is going to aid in solving when you get access to the main question.

The determination of the heat transferred from one substance to another is one of the important aspect in science. The method in which this heat is being measured is known as calorimetry and the instrument used in this technique is known as the calorimeter.

When the energy content of a snack is needed to be calculated, there is the need use a type of instrument known as bomb calorimeter.

Most of the calorimeters used by students are not so expensive like the used in the industries. Most of these calorimeters operates at a constant pressure while the Bomb Calorimeter operates at constant volume.

Mark brainly if answered correctly

Answers

ROW - ( 3 ) is correct

SYSTEM (A)

Respiratory system - here gaseous exchange takes place.

SYSTEM (B)

Digestive system - here nutrients from food is absorbed and assimilated .

SYSTEM (C)

Excretory system - removal of waste occurs

A lab requires 20.5g of KNO₃. How many moles of KNO₃ are being used in the lab. Your answer should include a correct numerical set up. What is the approximate percent by mass of the water in the hydrated salt? [Show all work.] *

Answers

Answer:

the answer is 0.2

Explanation:

we have a formula that mole= reacting mass/ molar Mass and the molar Mass of KNO3 is 101 so since mole is reacting mass/ molar Mass and our reacting mass is 20.5 then divided it by 101 it is equal to 0.2

¿Qué energías son usadas en la fabricación de las llantas desde la obtención de materia prima caucho natural, hasta el producto terminado ?

Answers

Answer:

yo te diria que el elastico amigo es esa

Is Palladium an elementary substance or a compound?

Answers

Answer:

Elementary substance, since it is in the periodic table of elements.

Hope that helps!

-SCSB

Explanation:

Which statement describes how echolocation and ultrasound imaging are the same? They both use the absorption of sound waves. They both use the diffraction of sound waves. They both use the reflection of sound waves. They both use the transmission of sound waves.

Answers

Answer:

C.) They both use the reflection of sound waves.

Explanation:

Right on Edge

Answer:

C.) They both use the reflection of sound waves.

Explanation:

stay safe 2021

Which element is in group 15 period 6? Periodic table 

Answers

Answer:

Bismuth ( Bi )

Explanation:

Describe the motion of the water molecules as the vapor pressure increases?

Answers

Answer:  As for vapor pressure being higher at higher temperatures, when the temperature of a liquid is raised, the added energy in the liquid gives the molecules more energy and they have greater ability to escape the liquid phase and go into the gaseous phase.

Explanation:

The motion of the water molecules as the vapor pressure increases is:

The water molecules have greater energy

According to the movement of the water molecules in a pressurized environment where the vapor and the temperature are increased, there is an increased ability to change from liquid to gas.

As a result of this, the water molecules has greater energy as they are subjected to increased levels of temperature and vapor pressure which makes them have more energy and to be more unstable.

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A student investigates the speed of a ball rolling down a ramp. The student records their data in the table below. Which of these best explains the student’s data?

A. The speed of the ball increases as the ball rolls down the ramp because the force acting on the ball is greater than the force of gravity.
B. The speed of the ball increases as the ball rolls down the ramp because the forces acting on the ball are unbalanced.
C. The speed of the ball decreases as the ball rolls down the ramp because the forces acting on the ball are balanced.
D. The speed of the ball decreases as the ball rolls down the ramp because of friction between the ball and the ramp.

Answers

Answer:

b

Explanationbecause i took the test and got a 100

the correct answer is b, the speed of the ball increases as the ball rolls down the ramp because the forces acting on the balls are balanced. hope this helps!! :)

please help people! science science! thank you!

Answers

Answer:

A. Is your answer

All the other ones are not valid because they are lower to the ground and you wouldn't have enough MOMENTUM to put you up for the top of the star.

Hope this helps!

how much atomic mass does Osmium have

Answers

Answer:

190.23g

Explanation:

Osmium is element number 76 on the periodic table, with the atomic symbol "Os." The atomic mass of any element is listed underneath the atomic symbol. Osmium has an atomic mass of 190.23 grams.

Read the article and answer the 6 questions in it.

Answers

Answer:

Yea.....where is the article and the 6 questions?

Answer:

Answering

Explanation:

do u want us to tell u what we got?

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