1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
mario62 [17]
2 years ago
15

2. In 1804, almost a century before the nucleus was discovered, the English scientist John Dalton provided evidence for the exis

tence of the atom. Dalton thought that atoms were the smallest particles of matter, which couldn't be divided into smaller particles. He modeled atoms with solid wooden balls. In 1897, another English scientist, named J. J. Thomson, discovered the electron. It was first subatomic particle to be identified. Because atoms are neutral in electric charge, Thomson assumed that atoms must also contain areas of positive charge to cancel out the negatively charged electrons. He thought that an atom was like a plum pudding, consisting mostly of positively charged matter with negative electrons scattered through it.
The nucleus of the atom was discovered next. It was discovered in 1911 by a scientist from New Zealand named Ernest Rutherford, who is pictured in Figure below. Through his clever research, Rutherford showed that the positive charge of an atom is confined to a tiny massive region at the center of the atom, rather than being spread evenly throughout the “pudding” of the atom as Thomson had suggested.

Question: Why did Thomson think that the atom also had to have a positive charge?

Question: What two particles are found in the nucleus?

3.Question: What particle did Rutherford discover in the nucleus?
4.Question: What did Rutherford predict was also in the nucleus?
5.Question: How did Rutherford describe the size of the nucleus?
6.Question: According to Rutherford, how was Thomson's model of the atom incorrect?
7.Question: How are all atoms of an element identical?
Chemistry
1 answer:
belka [17]2 years ago
3 0

Answer:

The Electron found by J.J Thompson

Explanation:

Hope this helps:)

You might be interested in
What cells do you think is in metaphase? why?
Tcecarenko [31]
Etaphase is a stage during the process of cell division (mitosis or meiosis). Usually, individual chromosomes cannot be observed in the cell nucleus. However, during metaphase of mitosis or meiosis the chromosomes condense and become distinguishable as they align in the center of the dividing cell.
3 0
2 years ago
As you move from bottom on the periodic table to the top shielding
masha68 [24]

Answer:

AS we move from bottom to top on periodic table shielding decreased.

Explanation:

As we move from left to right across the periodic table the number of valance electrons in an atom increase. The atomic size tend to decrease in same period of periodic table because the electrons are added with in the same shell. When the electron are added, at the same time protons are also added in the nucleus. The positive charge is going to increase and this charge is greater in effect than the charge of electrons. This effect lead to the greater nuclear attraction.

As we move down the group atomic radii increased with increase of atomic number. The addition of electron in next level cause the atomic radii to increased. The hold of nucleus on valance shell become weaker because of shielding of electrons thus size of atom increased.

As we move from bottom to top the energy level decreased because of decreased in electron thus shielding decreased and atomic size also decreased.

3 0
3 years ago
PLZ HELP I WILL GIVE BRAINLISTS TO RIGHT ANSWER
galina1969 [7]
..........The answer is B
6 0
2 years ago
What happens to water during evaporation?
kotegsom [21]
D would be your best bet because evaporation occurs when water is heated, it then vibrates and then magic!
5 0
3 years ago
Read 2 more answers
The activation energy of an uncatalyzed reaction is 70 kJ/mol. When a catalyst is added, the activation energy (at 20 °C) is 42
denis23 [38]

Answer:

T = 215.33 °C

Explanation:

The activation energy is given by the Arrhenius equation:

k = Ae^{\frac{-Ea}{RT}}

<u>Where:</u>

k: is the rate constant

A: is the frequency factor    

Ea: is the activation energy

R: is the gas constant = 8.314 J/(K*mol)

T: is the temperature

We have for the uncatalyzed reaction:

Ea₁ = 70 kJ/mol

And for the catalyzed reaction:

Ea₂ = 42 kJ/mol

T₂ = 20 °C = 293 K

The frequency factor A is constant and the initial concentrations are the same.

Since the rate of the uncatalyzed reaction (k₁) is equal to the rate of the catalyzed reaction (k₂), we have:

k_{1} = k_{2}

Ae^{\frac{-Ea_{1}}{RT_{1}}} = Ae^{\frac{-Ea_{2}}{RT_{2}}}   (1)

By solving equation (1) for T₁ we have:

T_{1} = \frac{T_{2}*Ea_{1}}{Ea_{2}} = \frac{293 K*70 kJ/mol}{42 kJ/mol} = 488. 33 K = 215.33 ^\circ C  

Therefore, we need to heat the solution at 215.33 °C so that the rate of the uncatalyzed reaction is equal to the rate of the catalyzed reaction.

I hope it helps you!      

4 0
3 years ago
Other questions:
  • Addition of 50. J to a 10.0-g sample of a metal will cause the temperature of a metal to rise from 25ºC to 35ºC. The specific he
    5·1 answer
  • What is the henry's law constant for co2 at 20∘c? express your answer to three significant figures and include the appropriate u
    11·2 answers
  • Any molecule that contains only carbon, hydrogen, &amp; oxygen atoms in a 1:2:1 ratio (e.g., c6h12o6) is a:
    11·1 answer
  • A graduated cylinder (approximate as a regular cylinder) has a radius of 1.045 cm and a height of 30.48 cm. What is the volume o
    12·1 answer
  • First answer will be brainliest!!
    15·1 answer
  • _____ are the results of a thoroughly tested hypothesis?
    9·1 answer
  • g, Assuming the precipitate is totally insoluble in water, which aqueous ions will be present in the solution (collected in the
    7·1 answer
  • Which functional group contains a nitrogen atom and an oxygen atom?
    14·2 answers
  • By how many times would you expect Al2(SO4)3 to depress the F.P of water compared to sucrose C12H22011 ?​
    11·1 answer
  • Mechanical waves travel fastest through<br> A -Solid<br> B -Liquid<br> C -Gas<br> D -Vacuum
    11·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!