answer.
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
zhenek [66]
2 years ago
11

The model of the atom has changed as scientists have gathered new evidence. Four models of the atom are shown below, but one imp

ortant model is missing.
An image at left with overlapping red and blue balls in the center with a circular fuzzy green cloud outside them. An image at center left with a purple ball in the center surrounded by overlapping concentric black ovals, each with a small green ball on each of the 6 ovals. An image at center right with a large black cross in a purple circle with a black line around the purple, with 10 small green balls dispersed within the purple circle.

Which atomic model is missing from this set?

Bohr’s model
Dalton’s model
Rutherford’s model
Thomson’s model

Physics
2 answers:
astraxan [27]2 years ago
8 0

Answer:

Daulton's model...  i took the test!

Explanation:

nexus9112 [7]2 years ago
4 0

Answer: Dalton’s model

Explanation:

In the attached image we can see four atomic models labeled with four letters:

W represents the current and accepeted atomic model: a nucleus with an electron cloud, where the orbit and position of the electrons around the nucleus is defined by specific regions (associated with specific energy levels) where there is a greater probability of finding the electron at any given moment. It is important to note this model was improved by the works in quantum physics done by Louis de Broglie and Erwin Schrodinger.

X represents Rutherford's model (This model was proposed after Thomson's model). Ernest Rutherford conducted a series of experiments in order to corroborate Thomson's atomic model. However the results of the experiment led him to find out there is a concentration of charge in the atom's core (which was later called nucleus) surrounded by electrons.  This lead to a new atomic model, in which the atom has a positive charged nucleus surrounded by negative charged particles that move similar to the orbit of the planet around the Sun.

Y represents Thomson's model, also called  the <em>plum pudding</em> model. This scientific found out that atoms contain small subatomic particles with a negative charge (later called electrons). However, taking into consideration that at that time there was still no evidence of the atom nucleus, Thomson thought the electrons were immersed in the atom of positive charge that counteracted the negative charge of the electrons. Just like the raisins embedded in a pudding or bread.

Z represents Bohr's model. This model was proposed by the danish physicist Niels Bohr after Rutherford's model. In fact, this model was Rutherford's model with the following addition: electrons orbit the nucleus (like planets around the sun) in specific orbits at different energy levels around the nucleus.

So, the only missing model is <u>Dalton's model</u>, which was the first atomic model:  the atom represented as a solid, indestructible and indivisible mass. An idea that was already accepted by that time since the ancient Greeks.

You might be interested in
A 0.242 g sample of potassium is heated in oxygen. The result is 0.292 g of a crystalline compound. What is the formula of this
masha68 [24]

Answer:

Hello there Dude answer is B :D hope it helped mark me brainliest.

8 0
2 years ago
Heat engines were first envisioned and built during the industrial revolution. Explain the thermodynamics of a heat engine comme
Artyom0805 [142]

Heat engines were developed during industrial revolution.

Generally a heat engine contains three parts i.e source, sink and working substance.

The source of a heat engine is present at a higher temperature as compared to the sink. Due to the temperature difference, the heat will flow from source to sink through working substance.

Let us consider  T_{1}\ and\ T_{2} are the temperature of source and sink.

As the source is at higher temperature as compared to sink, heat will flow from source to sink.

Let\ Q_{1}\ and\ Q_{2} are the heat provided by source and heat rejected to sink.

Hence, the work done by the working substance will be -

                                                W\ =\ Q_{1}-Q_{2}

The efficiency of a heat engine is defined as the ratio of output to the input energy.

Here output = workdone [W]

Hence, the efficiency of a heat engine is calculated as -

                     Efficiency\ [\eta]=\frac{W}{Q_{1}}

                                        \eta\ =\frac{Q_{1}- Q_{2}} {Q_{1}}

                                               =\ 1-\frac{Q_{2}} {Q_{1}}

This is the expression for the efficiency of heat engine.

Here, all the heat absorbed by the working substance can not be converted to desired output. The efficiency of a heat engine can not be 100 percent. Some amount of heat is lost in the form of sound and heat due to the friction which is produced due to the relative motion between various parts of the machine.

6 0
2 years ago
Read 2 more answers
Write the meaning of an object has 2 meter length
Ivahew [28]

Answer:

The object has 2 meter length. This means the length is any quantity with a dimension distance. The definition of the length is how long something is or amount of space. In the given data it is stated that, the object is something that has a length of 2 meter.  

<em>Let's take examples to understand. </em>

For example a thread or a table is an object which has a total length of 2 meters.  

Another example is something we are measuring it gives us a result of 2 meters of length by using a meter scale or meter tape.    

Length is a measure of distance and it is a fundamental quantity. Meter is a international system of units (SI units).    



 



4 0
2 years ago
A radioactive isotope has a half-life of 2 hours. If a sample of the element contains 600,000 radioactive nuclei at 12 noon, how
storchak [24]

Answer: There will be 75258 nuclei left at 6 pm.

Explanation:

a) half-life of the radioactive substance:

Half life is the amount of time taken by a radioactive material to decay to half of its original value.

t_{\frac{1}{2}}=\frac{0.69}{k}

k=\frac{0.69}{t_{\frac{1}{2}}}=\frac{0.693}{2hours}=0.346hours^{-1}

b) Expression for rate law for first order kinetics is given by:

A=A_0e^{-kt}

where,

k = rate constant  

t = time for decomposition = 6 hours ( from 12 noon to 6 pm)

A = activity at time t = ?

A_0 = initial activity  = 600, 000

A=600000\times e^{-0.346\times 6}

A=75258

Thus there will be 75258 nuclei left at 6 pm.

7 0
2 years ago
Steam at 0.6 MPa, 200 oC, enters an insulated nozzle with a velocity of 50 m/s. It leaves at a pressure of 0.15 MPa and a veloci
Rudiy27

Answer:

x2 = 0.99

Explanation:

from superheated water table

at pressure p1 = 0.6MPa and temperature 200 degree celcius

h1 = 2850.6 kJ/kg

From energy equation we have following relation

\dot m( h1+\frac{v1^2}{2}+ gz1 )+ Q = \dot m( h2+\frac{v2^2}{2}+ gz1) + W

\dot m( h1+\frac{v1^2}{2}) = \dot m( h2+\frac{v2^2}{2})

h1+\frac{v1^2}{2} = h2+\frac{v2^2}{2}

2850.6 + [\frac{50^2}{2} * \frac{1 kJ/kg}{1000 m^2/S^2}] = h2 +[ \frac{600^2}{2} * \frac{1 kJ/kg}{1000 m^2/S^2}]

h2 = 2671.85 kJ/kg

from superheated water table

at pressure p2 = 0.15MPa

specific enthalpy of fluid hf = 467.13 kJ/kg

enthalpy change hfg = 2226.0 kJ/kg

specific enthalpy of the saturated gas hg = 2693.1 kJ/kg

as it can be seen from above value hf>h2>hg, so phase 2 is two phase region. so we have

quality of steam x2

h2 = hf + x2(hfg)

2671.85 = 467.13 +x2*2226.0

x2 = 0.99

6 0
2 years ago
Other questions:
  • In an experiment the chemical reaction between a piece of aluminum foil and Copper(II)Chloride solution in a beaker is observed.
    12·2 answers
  • A kayaker needs to paddle north across a 100-m-wide harbor. the tide is going out, creating a tidal current that flows to the ea
    14·2 answers
  • What is the freezing point of radiator fluid that is 50% antifreeze by mass? k f for water is 1.86 ∘ c/m?
    7·2 answers
  • A hydrogen discharge lamp emits light with two prominent wavelengths: 656 nm (red) and 486 nm (blue). The light enters a flint-g
    15·1 answer
  • Mantles for gas lanterns contain thorium, because it forms an oxide that can survive being heated to incandescence for long peri
    8·1 answer
  • a rectangular coil of 25 loops is suspended in a field of 0.20wb/m2.the plane of coil is parallel to the direction of the field
    7·1 answer
  • A hot air balloon is on the ground, 200 feet from an observer. The pilot decides to ascend at 100 ft/min. How fast is the angle
    14·1 answer
  • The small piston of a hydraulic lift has a cross-sectional of 3 00 cm2 and its large piston has a cross-sectional area of 200 cm
    14·1 answer
  • A dog of mass 10 kg sits on a skateboard of mass 2 kg that is initially traveling south at 2 m/s. The dog jumps off with a veloc
    9·1 answer
  • Given a 100-watt power source, what is the maximum allowable length for the 24-guage transmission media if a signal of 1 Watt is
    9·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!