The clearer answer is they measure the remaining carbon, and the less that there is the older the fossil is.
Same number of valence electrons
Explanation:
Two elements posses similar chemical properties if they have the same number of valence electrons.
Chemical properties of any substance is determined by the number of valence electrons it possesses in its outer most shell.
Elements use their valence electrons to form chemical bonds with one another.
Elements with the same number of valence electrons will chemically combine the same way.
This is why elements in the same group on the periodic table have the same chemical properties.
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22-yes, they belong to the same group
23- they are metals
24-Atoms of group 1 elements all have one electron in their outer shell. This means Na and K have the same valence electrons.
25-Metals are solids at room temperature, therefore Na and K are solid.
26- mass number=A=235
Protons=z=92
Neutrons=mass number-protons
Neutrons=A-Z
Neutrons=235-92
Neutrons=143
Answer:
D: chain of volcanoes circling the Pacific Basin
Explanation:
First, we have to get moles of Mg2+ = molarity * volume
= 1 x 10^-2 * 0.15 L
= 0.0015 mol
initial [Mg2+] = 0.0015 / 0.4 L(total volume)
= 0.00375 M
then, moles of F- = molarity * volume
= 1 x 10^-1 * 0.25
= 0.025 Mol
initial [F-] = 0.025 / 0.4 = 0.0625 M
by using ICE table:
MgF2(s) → Mg2 + 2F-
initial 0.00375 0.0625
change + X +2 X
Equ 0.00375+X 0.0625+2X
when Ksp = [Mg2+][F-]^2
by substitution:
6.4 x 10^-9 = (0.00375+X)( 0.0625 +2X)^2 by solving for X
∴X= 0.00024 M
∴[Mg2+] = 0.00375 + X
= 0.00375 + 0.00024
= 0.004 M
and [F-] = 0.0625 + 2X
= 0.0625 + 2* 0.00024
= 0.06 M
