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.
Kepler's
third law shows the relationship between the orbital period of an object and
the distance between the object and the object it orbits.
The
simplified version of this law is: P^2 = a^3
Where,
P =
period of the orbit in years = 0.62 years
a =
average distance from the object to the object it orbits in AU. The
astronomical unit AU is a unit of length which is roughly equivalent to the
distance from Earth to the Sun.
Therefore
calculating for a:
0.62
^ 2 = a ^ 3
a =
0.62 ^ (2/3)
a =
0.727 AU = 0.72 AU
Therefore we can interpret this as: The distance from Venus to the Sun is about 72% of the distance from Earth to
Sun.
<span>Answer:
B. 0.72 AU</span>
I'd say b, but i'm not 100 percent sure.<span />
An example of an atom that has no charge is one that has a. 2 protons, 2 electrons, and 1 neutron.
To be neutral an atom must have the <em>same number</em> of protons (+) and electrons (-).
Only then will the <em>charges cancel</em> and give a neutral atom.
Answer:
410 nm
Explanation:
The highest frequency is associated with the shortest wavelength. Of those listed, 410 nm is the shortest.
