Answer:
A- beryllium
B- calcium
C- magnesium
Explanation
NOTE: all element in group 2 have 2 balance electrons
First let’s start with B- number of electrons= number of protons which is equal to the atomic number. therefore, the answer is calcium as it’s atomic number is 20
C- magnesium will have three energy levels considering it has 12 electrons (2,8,2).
A- beryllium is the lightest one in group 2 as it has the atomic mass of 9.0122.
<span>Melting is an endothermic process (i.e. it absorbs heat), whereas freezing is an exothermic process (i.e. it releases heat, or can be thought of, albeit incorrectly from a thermodynamics standpoint, as "absorbing cold"). The standard enthalpy of fusion of water can be used for both scenarios, but standard enthalpy is in units of energy/mass, so 10 times as much energy will be absorbed in the former scenario (melting 10 kg of ice) than what will be absorbed in the latter scenario (freezing 1 kg of water). For both processes, assuming the water is pure and at standard atmospheric pressure, and the entire mass remains at thermal equilibrium, the temperature of both the solid and the liquid will remain at precisely 0 degrees Celsius (273 K) for the duration of the phase change.</span>
It is a metal
hope it helps
Answer:
• A candle is burned
• Your silver teapot turns black
• Two clear colorless salt solutions are mixed and a bright orange precipitate forms.
Explanation:
A chemical change results from a chemical reaction of the species involved. Examples of chemical changes are burning, cooking, rusting etc.
Physical change when matter changes forms but not chemical identity. Examples of physical changes are boiling, melting, freezing, evaporation etc.