Democritus was the first to propose the idea of the atom. He said the atom was just this tiny, solid sphere. However, he used no scientific evidence to support his claim, so a guy named John Dalton did some experimenting and basically backed up Democritus' claim with evidence. Then, a guy named J.J. Thompson came along and said the atom was not solid and that is consisted of tiny negatively charged particles(electrons) and he came up with the Plum Pudding model which is just a tiny sphere with a punch of random scattered dots in it. After that, Ernest Rutherford did experiments and found that the tiny sphere is made up of mostly empty space with a tiny, dense, positively charged sphere inside of it, and the negatively charged particles just randomly float around it. Neils Bohr then said that the electrons take specific, circular, evenly spaced paths. Then, finally, we come to the Quantum Mechanical Model which is the one accepted today. This model basically vetos Bohr's idea and has a nucleus inside of an electron cloud, which is where the electrons are found.
Answer:
The element is strontium and the number of neutrons it have is 51.
Explanation:
Based on the given information, the ionic compound is,
XCl₂ ⇔ X₂⁺ + 2Cl⁻
X2+ is the ion of the mentioned element
As mentioned in the given question, the number of electrons of the element X is 36 and as seen from the reaction the charge present on the ion is +2. Now the atomic number will be,
No. of electrons = atomic number - charge
36 = atomic number - 2
Atomic number = 38
Based on the periodic table, the atomic number 38 is for strontium element, and the sign of strontium is Sr. Hence, the element X is Sr.
Now based on the given information, the mass number of the element is 89. Now the no. of neutrons will be,
No. of neutrons = mass number - atomic number
= 89 - 38
= 51 neutrons.
The answer should be: <span>D. The reaction rate is equal in both directions
In the equilibrium state, the rate of reaction to the right is same as the reaction to the left. Because of this, the concentration of the reactant and product will be kept same.
It might seem like the reaction is stopped because there is no change in the concentration, but it wasn't. Adding a reactant or product will break the equilibrium state.</span>
Answer:
The number of energy levels will increase.
Explanation:
As they are all Noble Gases, they are all in the same family. However, as you go further down the list of Noble Gases, the period number increases. The period number shows the number of energy levels. Hence, an increase in energy levels.
Answer: a + 2
Explanation: Alkali Earths or Group II has an ionization charge of a + 2. Alkali Metals have a ionization a + 1. Halogens or cold elements have a ionization of a +3.
