Answer:
The period 4 alkaline-earth metal has the name Calcium. An isotope of this element having 20 neutrons has a mass number of 40.
Explanation:
Looking at the periodic table 4th row for the alkaline-earth metal, we can find Calcium which has an atomic number of 20 (or protons number, or z). The mass number is given by the sum of protons and neutrons. If the number of protons in this case is 20 and the number of neutrons is also 20, the mass number A = 40.
Answer:
The percentage of Lake Parsons which has evaporated since it became isolated is 68.24%.
Explanation:
The concentration of salt dissolved in Lake Parson = 21.0 g/L
= In 1 L of lake Parson water = 21.0 g of salt
The concentration of salt in several nearby non-isolated lakes = 6.67 g/L
The salt concentration in Lake Parsons before it became isolated = 6.67 g/L
In 1 L of lake water = 6.67 g of salt
If 1 L of lake Parson water has 6.67 g of salt. Then 21.0 grams of salt will be in ;
Water evaporated = 3.15 L - 1 L = 2.15 L
The percentage of Lake Parsons which has evaporated since it became isolated:
Answer:
There is only one stable atom that does not have neutrons. It is an isotope of the element hydrogen called protium. Protium, which contains a single proton and a single electron, is the simplest atom. All other stable atoms contain some number of neutrons. hope this helps you :)
