Atoms are made of nucleus and electrons. Nucleus have a positive charge due to the presence of protons and electrons are negative in charge . Thus option 2 is correct.
Atoms are the basic unit every substance. Atoms combines to form molecules and compounds. An atom is made of nucleus and surrounding electrons which are revolving through a circular path of fixed energy.
Nucleus is the core of the atom and the 90% of the weight of atom is centered in the nucleus and it contains positively charged protons and neutral particles neutrons.
The nuclear model of atom was first proposed by Rutherford. He found the positive cloud of the atom and and named as nucleus. He discovered the positively charged particles protons.
The net charge of an atom is zero because all the positive charges are neutralised by equal number of negatively charged particles electrons.
Therefore, the nucleus is positive and the electron cloud is negative and option 2 is correct.
To find more about atomic nucleus, refer the link below:
#SPJ2
Carbon
Quartz
Hematite
b. The mass of the Carbon-14 sample is greater than the Carbon-12 sample, but the reactivity of both samples was the same .
c. The reactivity of the Carbon-14 sample is less than the Carbon-12 sample, but the mass of both samples was the same.
d. The reactivity of the Carbon-14 sample is greater than the Carbon-12 sample, but the mass of both samples was the same.
Answer:
B.
Explanation:
Correct: b. The mass of the Carbon-14 sample is greater than the Carbon-12 sample, but the reactivity of both samples was the same .
- C-14 has two additional neutrons, so is heavier than C-12. The chemical properties will be the same, however.
Explanation:
The principle used in the preparation of these salts is to dissolve
the cystine in an alcoholic alkali solution to which just sufficient
water to effect solution has been added, and, after filtering from
excess cystine, to precipitate the salt by addition of a suitable
indifferent solvent. While various solvents, such as acetone,
ether, or large amounts of alcohol caused precipitations, these were
either oily or amorphous. Only acetonitrile was found to possess
the power of initiating regular crystallization in the salt solutions.
While the solutions of the different salts require different amounts
of the solvent for complete precipitation, a partial substitution of
absolute ether for acetonitrile was found expedient in the case
of the most soluble of the salts, the K salt.
Answer:
It is simply a process of forming crystal.
Explanation: When salt is heated and dissolve in the liquid mainly water then its called saturated solution. When we further add salt and increase heat in order to dissolve it then it forcibly dissolve in liquid it's called supersaturated solution. After we slowly cool down the temperature then the salt we have put in supersaturated solution arises in the form of crystal. Hence its called crystalization.