Answer: A
Explanation:
This means that the atomic number decreases by 1 but the mass remains constant, meaning the atomic number of the new element is 20. This corresponds to calcium.
Answer:
being polar, it can easily dissolve other polar substances or substances with ionic bonds like nacl
Answer:Physical
Explanation:
State Change is physical because it changes without it being chemically done. So when water changes from a liquid to a solid the state of it is changing. (Solid or Liquid or Gas)
Basically what is physically being changed with out a chemical.
The two reason behind the invalidity of flame test are false positive and false negative.
while performing the flame test you must have to be accurate otherwise you will get false results may be positive for some element or may be negative in case the element is present. The main reason to get the false positive and false negative is the presence and contamination of sodium.
Rutherford performed gold foil experiment to understand that how negative and positive particles could Co exist in an atom. He bombarded alpha particles on a 0.00004 cm thick gold foil.
He proposed a planetary model of the atom and concluded following results and demonstrated that,
1. An atom produces a line spectrum.
2. An Electron revolves around the nucleus without any orbits.
3. Since most of the particles passed through the foil undeflected it means that most of the volume occupied by an atom is empty.
4. An Atom as a whole is neutral.
5. The deflection of few particles on the foil suggested that there is center of positive particles in an atom called the nucleus of the atom.
6. The complete rebounce of few particles on the gold foil suggested that the nucleus is very dense and hard.
