JJ Thomson discovered electrons using the cathode ray. Electrons are negatively charged particles that orbit around the nucleus of an atom. Finding out that there was a negative charge to balance out the positive charge. This later helped develop Hund's Rule and the Pauli Exclusion Principle.
Answer:

Explanation:
Hello there!
In this case, for the given reactants side, we infer this is a double replacement reaction because all the cations and anions are switched around as a result of the chemical change, we infer that the products side include aluminum with nitrate and magnesium with sulfate as shown below:

However, we need to balance since unequal number of atoms are present at both sides, thus, we do that as shown below:

Thus, we make 6 Al atoms, 3 S atoms, 3 Mg atoms and 30 O atoms on each side in agreement with the law of conservation of mass.
Regards!
Cells are organized into tissues. Tissues carry out specific functions. Groups of tissues can then form organs that also have specific functions to carry out. Lastly groups of organs form organ systems that regulate many functions in a specific part of the body.
Answer:
Atomic number of this isotope = 77
Explanation:
Given that,
Mass number = 193
No of neutrons = 116
We need to find the atomic no of this isotope.
We know that,
Atomic mass = No of protons + No. of neutrons
Also, atomic no = no of protons
So,
Atomic mass = atomic no + No. of neutrons
⇒ Atomic no = Atomic mass - no of neutrons
Atomic no = 193 - 116
Atomic no = 77
Hence, 77 is the atomic no of the isotope.