Explain how ideas about the atom have changed over time. 22 POINTS FOR A GOOD ANSWER !!!

2 answers:

8 0

John Dalton was the first to record his ideas about the atom; he thought that matter was made up of these tiny particles called atoms which he thought of as tiny spheres that couldn’t be divided.
Then J J Thompson carried out experiments that led him to discover the electron. Putting his discoveries together he settles on the now famous ‘plum pudding model’ that describes the atom as a ball of positive charge with negative electrons embedded throughout - much like that of currants in a Christmas pudding.
Ernest Rutherford then put together an experiment to test the ideas of the plum pudding model. He fired positively charged alpha particles at thin gold foil; most alpha particles went straight through however some were scattered in differing directions. From this he realised that the mass of the atom is concentrated in the centre (now know as the nucleus) and that the nucleus is positive.
The most up to date model as we know it is the idea of the positive nucleus containing protons and neutrons with orbitals containing negative electrons surrounding the nucleus in shells.

Alex777 [14]2 years ago

5 0

At first we thought atoms were just electrons and were negatively charged, but now we’ve learned that is can create different and many more substances.

You might be interested in

What is an example of a soultion

Marrrta [24]

Answer:

Did you mean solution??

In chemistry, a solution is considered as a special type of homogeneous mixture composed of two or more substances. In such a mixture, a solute is a substance dissolved in another substance, known as a solvent.

Eg: sweet tea or coffee (sugar added to solution)

bleach (sodium hypochlorite dissolved in water)

HOPE IT HELPS :)

3 0

3 years ago

which one of the following is an endothermic process?1.ice melting 2.water freezing 3.a boiling soup 4.the reaction of HCl and N

Llana [10]

<span>From the above given choices :
melting is an endothermic process</span>

8 0

3 years ago

A container holds 15.0 g of phosphorous gas at a pressure of 2.0 atm and a temperature of 20.0 Celsius. What is the density of t

erik [133]

<span>Density is a value for mass, such as kg, divided by a value for volume, such as m3. Density is a physical property of a substance that represents the mass of that substance per unit volume. We calculate as follows:

PV = nRT
PV = mRT/ Molar mass
m/V = P(molar mass)/RT
Density = P(molar mass)/RT
Density = 2.0 ( 30.97 ) / 0.08206 ( 20 + 273.15) = 2.57 g/L <----First option</span>

5 0

3 years ago

Read 2 more answers

The rate constant for a certain reaction is measured at two different temperatures:

Talja [164]

Answer: The activation energy Ea for this reaction is 22689.8 J/mol

Explanation:

According to Arrhenius equation with change in temperature, the formula is as follows.

$ln \frac{k_{2}}{k_{1}} = \frac{-E_{a}}{R}[\frac{1}{T_{2}} - \frac{1}{T_{1}}]$