Answer: 3d
Explantion:
1) Period 4 contains the elements with atomic numbers 19 through 36.
2) The elements with atomic numbers 19 (K) and 20 (Ca) fill the orbital 4s.
3) After that, as Aufbau's rule may help you to remember, the energy of the orbitals 3d is lower than the energy of the orbtitals 4p. So, the element 21 (Sc) start fillind the orbital 3d.
There are ten 3d orbitals, so the elements 21 through 30 fill the 3d orbitals.
Those elements, called transition metals are: Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn.
When the 3d orbitals are full, the next elements in the same period 4, fill the six 4p orbitals.
Since I cannot find the choices, I will tell you some of the benefits of electroplating in different industries. You can compare these benefits with the choices you have and choose the best fit.
1- Forms a protective layer to protect the material from the conditions of the atmosphere as the corrosion
2- Improves the appearance of some inexpensive materials and makes them look more appealing
3- Can enhance the electrical conductivity of materials
4- electroplating of zinc-nickel or gold can survive high temperatures
5- Sometimes hardens the material
6- Increases the thickness of the material
<span>a) The strong nuclear force
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Answer:
²⁵₁₁Na⁺
Explanation:
Details about the atom:
Number of electrons = 10 electrons
Number of neutrons = 14 neutrons
Number of protons = 11 protons
The atomic number of an atom is a good indicator of the type of atom we have been given.
From the subatomic particles, the number of protons is the same as the atomic number.
Since the number of protons is 11, its atomic number will be 11.
The element with atomic number 11 is sodium, Na.
To write a complete notation, we also need the mass number;
Mass number = number of protons + number of neutrons
Mass number = 11 + 14 = 25
The charge on the atom:
Charge = Number of protons - number of electrons = 11 - 10 = 1+
The element in isotopic notation is given as;
²⁵₁₁Na⁺
