The answer is 2 electrons.
The electron configuration of calcium is 2:8:8:2
Calcium has two electrons in its outermost shell. These are its valence electrons and are the ones used in bonding with other elements. Valence electrons of an atom are those electrons that are in its outer energy shell or that are available for bonding.
Calcium is a metal. When metals react with non-metals, electrons are transferred from the metal atoms to the non-metal atoms forming ions. The resulting compound is known as an ionic compound.
For example, when calcium metal reacts with chlorine gas, calcium gives up its two valence electrons and Chlorine accepts them resulting in a new substance called calcium chloride in which the two elements have ended up forming ionic bonds.
answer: 3g. 17kg+3 ÷ 0.25
Answer :
A = In
B = 27
C = 73
D = 49
E = 56
F = 54
G = 66
H = 108
I = 32
Explanation :
Atomic number is defined as the number of protons or number of electrons.
Atomic number = number of protons = number of electrons
Mass number is defined as the sum of number of protons and number of neutrons.
Number of neutrons = Mass number - Number of protons
Number of electrons = Number of protons - charge
Element Number of Number of Number of Atomic
symbol protons electrons neutrons mass
Co 27 27 31 58
In 49 49 66 115
Ta 73 73 108 181
Ba²⁺ 56 54 81 137
S²⁻ 16 18 16 32
Answer:
d.3.0
Explanation:
Step 1: Calculate the final volume of the solution
The final volume is equal to the sum of the volumes of the initial HCl solution and the volume of distilled water.
V₂ = 100 mL + 100 mL = 200 mL
Step 2: Calculate the final concentration of HCl
We will use the dilution rule.
C₁ × V₁ = C₂ × V₂
C₂ = C₁ × V₁/V₂ = 0.002 M × 100 mL/200 mL = 0.001 M
Step 3: Calculate the pH of the final HCl solution
Since HCl is a strong acid, [H⁺] = HCl. We will use the definition of pH.
pH = -log [H⁺] = -log 0.001 = 3
Okay, so even if I just gave you the answers, your teacher needs work on it too so it'll be easier/better if I just explain how to do it.
Basically, both sides need to have the same number of molecules. To do this, we make charts. This is the first side of number one:
Na - 1
Mg- 1
F - 2
The subscript gives F two molecules, and the other ones only each have one. This is the second side:
Na- 1
Mg- 1
F- 1
So they're not equal. To fix this, we add coefficients. These are numbers that are going to appear in the front of each compound/element and changes the number of molecules of the WHOLE compound/element. We need two F on the second side, so we'll put a coefficient of 2 in front of NaF. The new chart for the second side is this:
Na- 2
Mg- 1
F- 2
Now we've fixed the F, but now Na is off! So let's go to the first side again and see what we can do. We can put a 2 in front of the Na. The new chart is this:
Na- 2
Mg -1
F- 2
Now both sides are the same. The full new equation is:
2Na + MgF(sub2) = 2NaF + Mg
Basically, do this for all of them. Feel free to ask more questions.
