Answer:
The answer will be :
In year 1869
Russian scientist named Dmitri Mendeleev
Chart called Mendeeleves periodic table
increasing atomic masses
physical and chemical properties.
Hope this Helps
Best of luck !!
Answer:
Helium
Explanation: The ionization energy decreases from the top to bottom in groups. And increases from left to the right across a period. Therefor Helium has tge largest first ionization energy, while francium has one of the lowest.
Answer:
Group 7A
Explanation:
The group 7A elements consists of the most reactive non-metals on the periodic table.
This group is known as the group of halogens. They consist of element fluorine, chlorine, bromine, iodine and astatine.
- The elements in this group have the highest electronegativity values.
- They have 7 valence electrons and requires just one electron to complete their octets.
- This way, they are highly reactive in their search for that single electron.
Answer:
D
Explanation:
I think but it is an better attempt than the other guy answer.
The half life for C14 is 5730 years.
We assume that Carbon 14/ Carbon 12 ratio was steady for living organisms over time, the problem is actually telling us that

= 0.0725 =

ˣ
Take the natural logarithm and In on both sides.
ln(0.725) = ln

ˣ
= - 0.3216 = xln (

= -0.6931x.
So x = (-.3216) / (-0.6931) = 0.464
or
t/t₁/₂ = 0.464
So t = 0.464 x t₁/₂ = 0.464 * 5730 yrs = 2660 years.