Answer:
Lathanum .
Atomic number = 57
Symbol = La
Atomic weight = 138.9
No of energy orbitals = 6
Electronic configuration
![[Xe]6s^25d^1](https://tex.z-dn.net/?f=%5BXe%5D6s%5E25d%5E1)
Potential because it hasnt released yet
Answer:
The person’s kinetic energy is 1,025 J
Explanation:
Kinetic energy is a form of energy. It is defined as the energy associated with bodies that are in motion and this energy depends on the mass and speed of the body.
Kinetic energy is defined as the amount of work necessary to accelerate a body of a given mass and in a position of rest, until it reaches a given speed. Once this point is reached, the amount of accumulated kinetic energy will remain the same unless there is a change in speed or the body returns to its state of rest by applying a force.
Kinetic energy is represented by the following formula:

where Ec is kinetic energy, which is measured in Joules (J), m is mass measured in kilograms (kg), and v is velocity measured in meters over seconds (m/s).
In this case:
- v= 5

Replacing:

Solving:
Ec= 1,025 J
<u><em>The person’s kinetic energy is 1,025 J</em></u>
Answer:
See Explanation
Explanation:
1) Let us recall that;
Mass number = number of protons + number of neutrons
Where;
Number of protons = ?
Number of neutrons =20
Mass number =39
Number of protons = mass number - number of neutrons
Mass of protons =39 - 20= 19 protons
2) Atomic number = 13
Number of neutrons =14
Then the mass number =13 +14 =27
The symbol of the element is 27X13
The number of protons= the number of electrons =13
The atomic number is the same as the proton number =13