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.
I think that's right like this
Answer:
NaCl + AgF → NaF + AgCl
Explanation:
A double replacement reaction is a type of chemical reaction that occurs when two reactants exchange cations or anions to yield two new products.
From all the reactions given ,
- 2Na + Cl₂ → 2NaCl is an example of combination reaction because two or more reactants (Na & Cl₂) react with each other to form a single product (NaCl)
- H₂SO₃ → H₂O + SO₂ is an example of decomposition reaction because a single reactant (H₂SO₃) breaks down into two or more products (H₂O & SO₂).
- 2K + 2H₂O → 2KOH + H₂ is an example of displacement reaction because a highly reactive element (K) displaces a least reactive element (H) from its compound (H₂O).
- NaCl + AgF → NaF + AgCl is an example of double replacement reaction because there's an exchange between Cations (
&
) and Anions (
&
).
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