<span>John Dalton introduced a theory proposing that elements vary because of the mass of their atoms.
He said in his theory that all matter is made up of indivisible blocks called atoms. He also stipulated in his theory that elements are identical thus, have different sizes and masses.
Dalton's theory was different from Niels Bohr who proposed a new atomic model which was also commonly known as the modern atomic theory. Bohr's theory says that atoms are arranged in circular orbits around the nucleus. He patterned his model as the solar system.
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Answer:
It is the way of cleaning of impurities present in metals
Answer:
Part A:
Charge is 
Configuration is 
Part B:
Charge is 
Configuration is 
Part C:
Charge is 
Configuration is 
Explanation:
Monatomic ions:
These ions consist of only one atom. If they have more than one atom then they are poly atomic ions.
Examples of Mono Atomic ions: 
Part A:
For P:
Phosphorous (P) has 15 electrons so it require 3 more electrons to stabilize itself.
Charge is 
Full ground-state electron configuration of the mono atomic ion:

Part B:
For Mg:
Magnesium (Mg) has 12 electrons so it requires 2 electrons to lose to achieve stable configuration.
Charge is 
Full ground-state electron configuration of the mono atomic ion:

Part C:
For Se:
Selenium (Se) has 34 electrons and requires two electrons to be stable.
Charge is 
Full ground-state electron configuration of the mono atomic ion:

The reaction between 1 mole of NaOH and 1 mole of HCl creates 1 mole of NaCl and 1 mole of water. Meaning that the moles of HCl needs to equal that of NaOH for the solution to be considered equalized. That being said, you first need to find the numbers miles of HCl by multiplying the volume by the molarity to get 0.01 moles HCl. (1Mx0.01L=0.01). That means that you need 0.01 moles of NaOH. I hope that helps. Let me know if anything is unclear.
Isotopes are variants of a particular chemical element which differ in neutron number, and consequently in nucleon number. All isotopes of a given element have the same number of protons but different numbers of neutrons in each atom.
The term isotope is formed from the Greek roots isos ("equal") and topos ("place"), meaning "the same place".