eight
four
six
The answer is: four.
For example compound carbon dioxide (CO₂):
Electron configuration of carbon: ₆C 1s² 2s² 2p².
Electron configuration of oxygen: ₈O 1s² 2s² 2p⁴.
Carbon atom is sp2 hybridized, it has three sp2 orbitals and one p orbital, they form four bonds.
Oxygen has two p orbitals, they form two bonds (one sigma and one pi bond).
p orbitals from carbon and oxygen overlap and form pi bond.
The correct answer is (1) Chemical
Explanation:
A compound is the result of two or more chemical elements that bond to form new substances; for example, water is a compound because this contains two hydrogen atoms bonded to one oxygen atom. Moreover, compounds are the result of a chemical change that occurs as two or more substances interact in a chemical reaction, and this leads to the formation of bonds between the substances or the formation of compounds.
On the other hand, a physical change involves only a change in the state of the matter and a nuclear change leads to a change in the atom rather. Thus, the type of change that must occur to form a compound is a chemical change.
The correct answer for above statement is:
C. Displacement.
Explanation:
Displacement reaction is a chemical reaction in which a bounteous reactive element replaces a less reactive element from its compound. Both metals and non-metals take part in displacement reactions. Example: Reaction of iron nails with copper sulfate solution.a type of chemical reaction wherever an element counters with a compound and takes the position of another element in that compound.
All atoms can be identified by the number of protons and neutrons they contain. The number of protons present in the nucleus of an atom of potassium - 42 is 19.
The particles which are smaller in size than an atom are called subatomic particles. An atom contains three sub atomic particles, they are protons, electrons and neutrons. The positively charged particles are called protons whereas the negatively charged particles are electrons.
The neutrons are chargeless particle. Here K - 42 is a radioactive isotope which has the atomic number 19. So the number of protons is 19 and the number of neutrons is:
A = Z + N
N = A - Z
= 42 - 19 = 23
The number of protons or electrons is the atomic number whereas the mass number is the sum of protons and neutrons.
Thus the number of protons is 19 and neutrons is 23.
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c. Sodium
b. Chromium
d. Iron