Answer:
True
Explanation:
It is true that every element in the periodic table follows the Aufbau's principle.
The principle states that "the sublevels with lower energies are filled up before those with higher energies".
- Sublevels do not fill up in numerical order.
- This is true when writing the electronic configuration of all atoms on the periodic table.
Answer:
Cac2 is a answer please mark me brainliest
The half life of a substance is the time taken by a radioactive substance to decay by half its original mass. In this case, the half life of Potassium-40 is 1.3 billion years.
Original mass of Potassium-40 = 12 g (100%)
New mass after the decay = 3 g ( 25 %, since 75% was replaced by argon)
New mass = Original mass × (1/2)^n ; where n is the number of half lives.
3 = 12 × (1/2)^n
(1/2)^n = 1/4
n = 2
Therefore; the time taken will be 1.3 × 2 = 2.6 Billion years
Answer is: <span>an atomic radius.
</span>The atomic radius<span> of a </span>chemical element<span> is a measure of the size of its atom.
</span>The atomic radius varies with increasing atomic number, but usually increases because of increasing of number of electrons.
The atomic radius decreases across the periods because an increasing number of protons, because <span>greater attraction between the protons and electrons.</span>
Reduction is only one half of the reaction of a redox (reduction-oxidation reaction). It is characterized by the reduction of oxidation number or the gain of electrons. So, you would expect the reaction to have moles of electrons in the reactant side to depict gaining of electrons. The reduction reaction is as follows:
<em>HNO₂ + e⁻ --> NO</em>
Why only 1 e-? Compute the oxidation number of N in the reactant side.
1+x+2(-2) = 0; x = +3
Then, compute the oxidation number of N in the product side.
x -2 = 0; x = +2
So, there is a difference of 1 electron. Hence, 1e-.
