How did chemists change Mendeleev's periodic table in the early 1900s?

Answers

Answer 1

Answer:

They used atomic number instead of atomic mass to organize the elements. From an element's location in the periodic table, you can predict: ... The elements have similar properties.


Related Questions

A gas occupies 1.00cm^3 at STP. What volume does it occupy at 710.0 mm Hg and 55.0°C

Answers

Answer:

Final volume is 1.29cm³

Explanation:

Using combined gas law:

P₁V₁/T₁ = P₂V₂/T₂

Where P is pressure, V volume and T absolute temperature of 1, initial state and 2, final state of a gas.

We can solve the volume of the gas:

P₁ = 1atm at STP

V₁ = 1cm³

T₁ = 273.15K at STP

P₂ = 710mmHg * (1atm / 760mmHg) = 0.9342atm

V₂ = ?

T₂ = 55.0°C + 273.15K = 328.15K

Replacing:

1atm*1cm³/273.15K = 0.9342atm*V₂/328.15K

1.29cm³ = V₂

Final volume is 1.29cm³

How does Bohr’s model of the atom compare with Thomson’s model?

They both describe atoms as small, indivisible spheres.
They both describe electrons as moving around the nucleus.
They both describe electrons as being surrounded by the positive matter.
They both describe atoms as being made up of positive and negative matter.

Answers

Answer:  They both describe atoms as being made up of positive and negative matter.

Answer:

They both describe atoms as being made up of positive and negative matter.

Explanation:

I did it on edge

PLEASE HELPPP!!!!!! ASAP!!!!



Which of the following best describes cations? Question 19 options: A) They're negatively charged because they lost an electron. B) They're positively charged because they gained an electron. C) They're positively charged because the number of electrons remained the same. D) They're positively charged because they lost an electron.

Answers

Answer:D

Explanation:trust me bro

Answer:

D

Explanation: I took the test

Look at the picture. If one of the lightbulbs breaks or is removed, what will happen to the other lightbulb?

2 bulbs and a battery in a single loop of wire.

Question 2 options:

It will stay on


It will go off


It will change colors


It will burn out

HERES ANOTHER FOR YOU GUYS! :)

Answers

Answer:

It will go off.

Explanation:

Since the two bulbs are connected in series with the battery, when one bulb breaks breaks the circuit hence flow of current is stopped from moving to the other bulb

A common organic compound is analyzed and found to contain 40.00% carbon, 6.71%, and 53.29%. Determine the empirical formula
A)
CH2O
B)
C₂H₂O₃
C)
C6HO8
D)
C6H12O6

Answers

Answer: CH2O I just did the question

Explanation:

Empirical formula is the simplest whole number ration of elements in a compound. Molecular formula is n times where n is integers 1,2,... Therefore, the empirical formula that is 40.00% carbon, 6.71% hydrogen, and 53.29% oxygen is CH[tex]_2[/tex]O.

What is empirical formula?

Empirical formula gives the proportion of the element that is present in a compound. It does not give information about the actual number or the arrangements of the atoms.

Number of gram atoms in compound = percentage of that element ÷Molar mass of that element

Molar mass of carbon=12

Molar mass of hydrogen =1

molar mass of oxygen=16

C= 40.00%÷24=1.66

H= 6.71%÷1=6.71

O=53.29%÷/16=3.33

The atomic ratio is1.66:6.71:3.33. Dividing by smallest whole number, the Whole number ratio is C:H:O is 1:2:1. Empirical formula corresponding to this whole number is CH[tex]_2[/tex]O.

Therefore, the empirical formula that is 40.00% carbon, 6.71% hydrogen, and 53.29% oxygen is CH[tex]_2[/tex]O.

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state modern periodic law ?arrange the element of halogen family in the increasing order of their number of Shell ?what type of Bond formation exists between the element of group 1 and 17 and why?​

Answers

Answer:

Modern periodic law states that the properties of elements are dependent on their atomic numbers and elements show similar properties at regular interval of increasing atomic number.

Question 2 :

FluorineChlorineBromineIodineAstatine

Question 3 :

3. Ionic Bond .

Reason : The elements from Group I are metals ( they lose electrons )

The elements from Group 17 are non-metals ( they Gain electrons

The Venn diagram describes a phase change from solid to gas phase between the areas marked

A. B and C
B. A and C
C. A and B
D. None of these

Answers

i believe the answer would be A and C

2. As an airplane moves forward, the shape of its wings causes a difference in pressure
below and above the wings. What is the effect of this difference in pressure?
A a downward force la created
B. the airplane speeds up
C. an upward force la oreated
D. the airplane slowa down

Answers

Answer:

C. An upward force is created

Explanation:

As an airplane moves forward, the shape of its wing creates lower pressure above the wing than below, yielding a net upward force known as lift.

Hope this helps!

Compare and contrast The two methods of making alcohol

Answers

Answer:

The table compares making ethanol by hydration of ethene (ethene and steam) to making ethanol by fermentation (sugar from plant material).

When sodium atoms (Na) and chlorine atoms (CT) join to make sodium chloride, or table salt, they form an ionic bond, Using this information, which pair of elements is most likely to form an ionic bond? O potassium (K) and fluorine (F) aluminum (AI) and aluminum (AD O sulfur (S) and oxygen (O) O calcium (Ca) and neon (Ne)​

Answers

Answer:

D I'm pretty sure.

Explanation:

I'm taking the quiz right now and D makes the most sense.

Answer:

d

Explanation:

What's wrong with the statement "a mug of hot chocolate contains more heat than a glass of cold water."

Answers

Answer:

Heat is not something that can be contained since it is not a tangible thing. Heat is a process

Explanation:

The wrong thing in this statement "a mug of hot chocolate contains more heat than a glass of cold water."is: Heat is a process. Heat is not something that can be contained since it is not a tangible thing.

What is Heat ?

Heat can be defined as a state or quality of being hot or in a high temperature.

Heat can also be said to be a transfer of kinetic energy from one environment to another, from one medium to another, or from one object to another.

In conclusion, Heat is a process. Heat is not something that can be contained since it is not a tangible thing.

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The Princess cruise ship left San Francisco and traveled south for 8 hours at a speed of 30mph. What is the velocity of the ship? Round your answer to the hundreths place

Answers

Answer:

v = 300 mph due South.

Explanation:

Given that,

The Princess cruise ship left San Francisco and traveled south for 8 hours at a speed of 30mph.

We need to find the velocity of the ship. It can be calculated by total distance divided by total time taken.

Velocity is a vector quantity i.e. it has both magnitude and direction. On the other hand, the speed has only magnitude (scalar quantity).

In this case it is mentioned that the cruise is travelling south with a speed of 300 mph.

Hence, the velocity is 300 mph in South direction.

Given the following two quantities: 0.50 mol of CH4 and 1.0 mol of HCl,
a. Which has more atoms?
b. Which has more molecules?
c. Which has the greater mass?
d. Which has the greater volume at the same temperature and pressure (both are gases)?

Answers

Answer:

(a) HCl

(b) HCl

(c) HCl

(d) HCl

Explanation:

Given: 0.50 mol of CH₄ and 1.0 mol of HCl

Using stoichiometry we can calculate the answers to parts a, b, c, and d.

Part (a)

# of moles × Avogadro's number = # of atoms or molecules

Avogadro's number: 6.02 * 10²³

[tex]\displaystyle 0.50\ \text{mol CH}_4 \cdot \frac{6.02\cdot 10^2^3 \ \text{atoms CH}_4}{1 \ \text{mol CH}_4} = 3.01 \cdot 10^2^3 \ \text{atoms CH}_4[/tex] [tex]\displaystyle 1.0\ \text{mol HCl} \cdot \frac{6.02\cdot 10^2^3 \ \text{atoms HCl}}{1 \ \text{mol HCl}} = 6.02 \cdot 10^2^3 \ \text{atoms HCl}[/tex]

HCl has more atoms than CH₄.

Part (b)

This is calculated the same way as Part (a); HCl has more molecules than CH₄.

Part (c)

Molar mass of CH₄ = 16.04 g/mol

Molar mass of HCl = 36.458 g/mol

[tex]\displaystyle 0.50\ \text{mol CH}_4 \cdot \frac{16.04 \ \text{g CH}_4}{1 \ \text{mol CH}_4} = 8.02 \ \text{g CH}_4[/tex] [tex]\displaystyle 1.0\ \text{mol HCl} \cdot \frac{36.458 \ \text{g HCl}}{1 \ \text{mol HCl}} = 36.458 \ \text{g HCl}[/tex]

HCl has a greater mass than CH₄.

Part (d)

Assuming STP:

Molar volume of any gas at STP is 22.4 L/mol.

[tex]\displaystyle 0.50\ \text{mol CH}_4 \cdot \frac{22.4 \ \text{L CH}_4}{1 \ \text{mol CH}_4} = 11.2 \ \text{L CH}_4[/tex] [tex]\displaystyle 1.0\ \text{mol HCl} \cdot \frac{22.4 \ \text{L HCl}}{1 \ \text{mol HCl}} = 22.4 \ \text{L HCl}[/tex]

HCl has a greater volume than CH₄.

what is the y and x axis?​

Answers

Answer:

x is horizontal

y is vertical

Explanation:

what does newton’s first law of motion explain

Answers

Answer:

Newton's first law states that, if a body is at rest or moving at a constant speed in a straight line, it will remain at rest or keep moving in a straight line at constant speed unless it is acted upon by a force.

Balancing Equations
Fe + O2 --> Fe2O3

Answers

Answer:

4Fe + 3O2 --> 2Fe2O3

Explanation:

Which image best represents a solution of distilled water at pH = 7? A cylinder contains many pale blue balls and 3 purple balls. A box has a pale blue ball with the label H + and a purple ball with the label O H negative. A cylinder contains about equal numbers of pale blue balls and purple balls. A box has a pale blue ball with the label H + and a purple ball with the label O H negative. A cylinder contains 3 pale blue balls and many purple balls. A box has a pale blue ball with the label H + and a purple ball with the label O H negative.

Answers

Answer:

The answer would be B

Explanation:

got it right on edge2021

A pH of 7 indicates neutrality of the solution. A solution will be neutral when it contains equal number of H+ and OH- ions. Thus, the cylinder with containing equal number of purple and pale blue balls represents the solution with pH of 7.

What is pH?

pH of a solution is the measure of its H+ ions concentration. Mathematically it is the negative logarithm of H+ ion concentration. pH of the solution determines the acidity or basicity of the solution.

A solution with pH of 7 is neutral. Thus having no acidity or basicity. The acid-base reaction neutralize each other forming their salt with pH of 7 and it is called neutralization reaction.

The solution with a pH below 7 is acidic and the solutions with pH above 7 are basic solutions. Bases are proton acceptors and they furnish OH- ions when ionized.

The solution with equal number of H + and OH- ions neutralize each other and thus have a pH of 7. Therefore, the cylinder with equal number of blue and purple balls represents the neutral water.

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Matter that is made up of only one kind of Atom

Answers

Answer:

elements

Matter that has only one kind of atom is called an element. Gold, copper, oxygen, and mercury are examples of elements. Most matter is made up of two or more different kinds of atoms that are chemically combined. This kind of matter is called a compound.

Explanation:

Answer:

Element

Explanation:

This is the answer because:

1) All matter is made up of substances called elements.

2) Matter that iis made up of only one kind of Atom is called an Element.

Hope this helps! :D


Calculate the number of atoms in 3.21 mole of Mg?

Answers

Answer:

1.93 × 10²⁴ atoms

Explanation:

The number of atoms in a substance can be found by using the formula

N = n × L

where n is the number of moles

N is the number of entities

L is the Avogadro's constant which is

6.02 × 10²³ entities

From the question we have

N = 3.21 × 6.02 × 10²³

We have the final answer as

1.93 × 10²⁴ atoms

Hope this helps you

Use dimensional analysis to convert 74.9 dry quarts to liquid quarts.

Answers

Answer:

87.2 liquid quarts (US)

HURRY ANSWER NOW AND I GIVE BRAINLY!!! HURYYY
1. A student left a sealed jar of water outside her home. Water can be a solid, liquid, or gas. When she put it outside, the water was a solid. Twelve hours later, the water had changed phase and was a liquid. What happened to the water molecules?

Answers

When the student left the jar outside, the molecules were moving around each other. Later, the molecules were moving away from each other.

Answer:

A. "before the student left, the molecules we're moving in place. After, the molecules we're moving around each other.

Explanation:

Hope this helps. Please mark as brainliest if it did. :)

explain how transferring energy into or out of a substance changes the molecules kinetic energy and changes their freedom of movement

Answers

Answer:

Transferring energy into or out of a substance changes its temperature, which changes the molecules' freedom of movement. Claim 2: Transferring energy into or out of a substance changes the molecules' kinetic energy, which changes their freedom of movement.

Which term is defined as the region in an atom where an electron is most likely to be
located?
1.
nucleus
2.
orbital
3.
quanta
4.
spectra

Answers

Answer:

"2.Orbital." I think

Explanation:

Risk*

What is the conversion for 2.0 m + 3.33 m + 4 m =

Answers

Answer:

933/100

9.33m

....... . . . . .. .. .

Someone help me answer this please! I’ll mark you brainliest

Answers

b. increase in surface area

Further explanation

Given

Speeding up a chemical reaction

Required

Factors used to speed up reactions

Solution

There are several factors that influence reaction kinetics :  

1. Concentration  

2. Surface area  

3. Temperature  

4. Catalyst  

5. Pressure  

6. Stirring  

Temperature is related to the kinetic energy of the particles. Heat is absorbed causes the particles of matter to move faster so that the reaction can take place faster

The enlarged surface area of the reactants causes more particles to react with other particles.

50 g square block of sulfur can be broken into small pieces or powdered so that more particles come into contact with each other

¿Cuál es el % en masa de una disolución de 1800 gr. De agua de jamaica si se le agregaron 120 gr. De azúcar?

Answers

what‍♂️huh wait hold up

HELP HELP HELP HELP HELP HELP HELP

Answers

Well, the answer to this question is B.
Also, I just want to say Happy new year to you and have a great rest of your day!
Also, can you please mark my answer as the brainliest answer?
Thank you!

A science teacher gave a student a sample of a clear liquid labeled "unknown
substance." Which property would best help the student determine the
sample's identity?

A. The sample's boiling point

B. The sample's mass

C. The sample's volume

D. The sample's weight

Answers

Answer:

A. The sample's boiling point

Explanation:

Because by knowing boiling point we easily find a substance for example if given clear liquid boiling point is 100 c° we immediately know this is water.

Moreover boiling point is a fixed quantity for a substance.

Answer this please if you do i will give you brainilset if you get it correct

Answers

Answer:

D

Explanation:

Describe what happens when two negatively charged particles interact with one another. (plz help 40 points!)

Answers

Answer:

When two negatively charged particles interact with one another, the particles repel with each other. Opposite charges attract while like charges repel. A negatively charged object will exert a repulsive force upon a second negatively charged object.

Explanation:

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