your answer will be :
B. <u>Na has a lower</u> <u>electronegativity than H</u>
because Na belongs to alkali metals which are least electronegative (most electro positive) but hydrogen is a non metal, it has higher electronegativity as compared to metals like Sodium (Na).
Answer:
Physical changes are changes that do not alter the identity of a substance. Chemical changes are changes that occur when one substance is turned into another substance.
Explanation:
Answer: 
Explanation:
Lattice energy : It is defined energy released when ions combine together in a gaseous phase to form a compound. it is energy possessed by the crystal lattice of a compound. Denoted by symbol 
.
, energy is absorbed while forming of the lattice
, energy is release while forming of the lattice
One mole of sodium ion when combines with one mole chloride ion release 786 kJ of energy.
<span>Respiration breaks down the sugar inside its cells. i have answered the question WHEN A PLANT UNDERGOES RESPIRATIONS IT WHAT HAPPENS</span>
The boiling of water and sublimation of iodine crystals are endothermic processes.
Answer: Option B & C
Explanation:
Endothermic process are the classifications of chemical reactions where the heat is absorbed by the system from the surroundings. As the matters can exists in three phases like solid, liquid and gases.
The endothermic process occurs by absorption of heat energy by the system. So according to the given options, the boiling of water and iodine crystal sublimation follows endothermic process. In the boiling of water occurs when the water molecules absorb heat from the surrounding and convert to gas phase.
Similarly, the sublimation of iodine crystals also require heat energy from the surrounding to break the bonds of the iodine crystals to sublimate to gas phase. Thus the boiling of water and sublimation of iodine crystals are the examples of endothermic processes.
