Answer:
35.48 uma
Explanation:
An isotope is when an element has equal numbers of protons but different mass value because it has different amount of neutrons.
To calculate the average atomic mass with the given data:
First change de percentages to fractional numbers, divide by 100.
Remember the sum of a percentage is equal to 100, but when you are adding the fractions the sum is equal to 1.
76/100 = 0.76
24/100 = 0.24
% fraction
76.00 0.76
24.00 0.24
total100.00 1.00
Now, multiply the mass with their corresponding fraction:
35(0.76) = 26.60
37(0.24) = 8.88
% fraction amu amu
76.00 0.76 35 26.60
24.00 0.24 37 8.88
total100.00 1.00 average 35.48
Now you add the calculated mass to obtain the average atomic mass of the element.
And the value you will get is 35.48 amu.
I included an excel table so you can review it, I like to organize all the given data and the calculation in tables, also I think is easier to understand.
Answer:
Explanation:
The reactivity of elements in the periodic table is based on the number of electrons in there outermost shell. Elements (metals) that have few electrons in there outermost shell are highly reactive because it is easier to lose fewer number of electrons (in the outermost shell during a reaction) than to lose more electrons in the outermost shell - thus metals that have one electron in there outermost shell are most reactive and are more reactive than those that have two electrons in there outermost shell. Hence, metals in group 1 are the most reactive metals because they all have one electron in there outermost shell.
Non-metals that have fewer electrons to complete there octet configuration are highly reactive because it is easier to gain fewer number of electrons (in the outermost shell during a reaction) than to gain more number of electrons - thus nonmetals that have seven electrons in there outermost shell are more reactive than nonmetals that have six electrons in there outermost shell. Hence, nonmetals in group 17 are the most reactive nonmetals because they contain seven electrons and have just one electron left to complete there octet configuration.
<span>D.) Rates of soil erosion are much lower during droughts that last several years.</span>
Answer:
Mixing of salt is physical change.
Explanation:
Mixing of salt is physical change because no chemical reaction occur between them. Sand is non polar while salt is polar.
Physical Change:
The changes that occur only due to change in shape or form but their chemical or internal composition remain unchanged.
These changes were reversible.
They have same chemical property.
These changes can be observed with naked eye.
Chemical change:
The changes, that occur due to change in the composition of a substance and result in a different compound is known as chemical change.
These changes are irreversible
These changes occur due to chemical reactions
These may not be observed with naked eye
Answer: only the VSEPR mode shows the geometric shape of a formula.
