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:
28500 years
Explanation:
Applying,
A = A'(
)............... Equation 1
Where A = Original mass of Carbon-14, A' = Final mass of carbon-14 after decaying, x = total time, y = half-life.
From the question,
Given: A = 1 g, A' = 31.3 mg = 0.0313 g, y = 5700 years.
Substitute these values into equation 1
1 = 0.0313(
)
= 1/0.0313
= 31.95
≈ 32
≈ 2⁵
Equating the base and solve for x
x/5700 ≈ 5
x ≈ 5×5700
x ≈ 28500 years
Answer:
state of matter
Explanation:
Because there are three state of matter namely:liquid,solid and gas and oxygen is a gas.
1 and 3 only because metal are easily to loss electron while non metal are difficult to loss electron that's why it called heavy elements.
Answer:
<em>In equipment reliability, the likelihood that a given event will occur</em>
Explanation:
