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olasank [31]
3 years ago
7

Use the helium-4 isotope to define atomic number and mass number. why does knowledge of atomic number enable us to deduce the nu

mber of electrons present in an atom
Chemistry
1 answer:
Nuetrik [128]3 years ago
8 0
Helium - 4 isotope has 2 protons and 2 neutrons.

Its atomic number is 2 (the number of protons). Atomic number is the number of protons in the atom of an element and it identifies the element. All the isotopes of an element have the same atomic number (same number of protons). So, all the isotopes of hellium have 2 protons.

The number 4 that identifies the helium - 4 isotope is the mass number, i.e. the number of protons plus the number of neutron. So, helium-4 isotope has 2 protons and 2 neutrons. While, other isotopes of helium have 2 protons but different number of neutrons.

The atomic number enable us to deduce the number of electrons in an atom because the atoms are neutral, which implies that the positive and negative charge are equal. Given that the magnitude of the charge of electons and protons are equal but the sign is opposed (protons are positve and electrons are negative) the number of electrons in the atom equals the number of protonts. That is why the atomic number is also the number of electrons of the atom.
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Helppppppppppppppppppppp
alukav5142 [94]

decameters - meters: multiply by 10

meters to meters: multiply by 1

centimeters to meters: divide by 100

millimeters to meters: divide by 1000

For the rows at the bottom:

hectometer row: 100, multiply by 100, 4500

decameter row: 10, multiply by 10, 450

meter row: 1, multiply by 1, 45

decimeter row: 0.1, divide by 10, 4.5

centimeter row: 0.01, divide by 100, 0.45

im guessing theres a millimeter row at the bottom:

millimeter row: 0.001, divide by 1000, 0.045


hope this helps!

5 0
3 years ago
Choose the number of significant figures indicated 0.06
Alex17521 [72]

Answer:

2

Explanation:

8 0
3 years ago
How many moles in 6.57 x 10^24 formula units of NaCl?
laiz [17]

Answer:

3.955*10^48

Explanation:

1 mole of a substance gives 6.02*10^23/6.57*10^24 will give x then cross multiply the answer. is 3.955*10^48

8 0
3 years ago
Comparing weak acids and strong acids of equal concentrations which of the following statements is true The pH of the weak acid
Firlakuza [10]

Answer:

the true statement is... The pH of the weak acid will be higher than the pH of the strong acid

Explanation:

pH is a measured of the extent to which acids dissociate into ions when plced in aqueous solution.

Strong acid dissociate near-completely, and weak acids barely dissociate.

At equal concentrations, a strong acid will have a lower pH than a weak acid, since the strong one will donate more proton to the solution.

6 0
3 years ago
Pls answer these and show work
Assoli18 [71]

There's no question??

\

8 0
2 years ago
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