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.
According to the calculation, set I is both the most accurate and most precise.
Exactness is a quality or state of being precise. 2a: comparison accuracy sense: the degree of precision with which an action is carried out or a measurement expressed 2b. The novel was fact-checked for historical authenticity. 2a: conformance to truth, to a standard, or to a model: exactness It is impossible to estimate the number of casualties with accuracy. Let's calculate the precision for the fourth set, considering
Δ1 = ∣(8.41−8.56)∣ g=0.15 g
Δ2 = (8.72−8.56) g=0.16 g
Δ3 = ∣(8.55−8.56)∣ g=0.01 g
Therefore: 
Learn more about accuracy and precision here:
brainly.com/question/28289139
#SPJ4
Answer:
Their average kinetic energy increases
Explanation:
The average kinetic energy of the rice molecules increases as the pot is left on the cooking stove.
Heat is transferred to the pot by conduction from the heat source. The heat is then transferred to the rice in the cooking pot by convection.
- As the water in the pot heats up.
- The rice gains thermal energy.
- This causes the molecules of the rice particles to start vibrating.
- As the molecules vibrate about their fixed position, their thermal energy continues to increase.
- Therefore, the amount of heat absorbed by the rice increases with time and this actually cooks the food.
