3.Write the symbol of the element that has a charge of +1 when it has 71 electrons.
1 answer:
The symbol :
There are two components that accompany an element, the mass number and atomic number
Atoms are composed of 3 types of basic particles (subatomic particles): <em>protons, electrons, and neutrons </em>
The Atomic Number (Z) indicates the number of protons and electrons in an atom of an element.
Atomic number = number of protons = number of electrons ⇒ neutral number
Atomic mass is the sum of protons and neutrons
Atomic Number (Z) = Atomic mass (A) - Number of Neutrons
The element has 71 electrons and a charge of +1 , so
Number of protons = 71 + 1 = 72
Number of protons = the atomic number = 72
The element with atomic number 72 is Hafnium(Hf)
The atomic mass of Hf = 178 g/mol
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Answer:
The number of atoms present in one unit of the following compounds is:
a). Potassium Iodide , KI = 2
b).Sodium Sulfide, = 3
c). Silicon Dioxide , = 3
d). Carbonic Acid , = 6
Explanation:
Atomicity : It is defined as the number of atoms that are present in a given molecule/compound.
Atom : The smallest unit of matter is called atom. For e.g O is atom of oxygen but is not an atom , it is molecule of oxygen .
molecule has 2 atoms of Oxygen
Similarly Na , K , Fe are atoms but ,
,
,
are molecules
a).Potassium Iodide
KI = 1 atom of K + 1 atom of I
Total atoms = 2
b) Sodium Sulfide
= 2 atoms of Na + 1 atom of S
Total atoms = 3
c) Silicon Dioxide
= 1 atom of Si + 2 atoms of O
Total atoms = 3
d) Carbonic Acid
= 2 atom of H + 1 atom of C + 3 atom of O
= 2+1+3
Total atoms = 6
Answer:
ΔH = 57 Kj/mole H₂O
Explanation:
