$(a)$ Write the chemical symbols of two elements:
$(i)$ which are formed from the first letter of the element's name.
$(ii)$ whose name has been taken from the names of the elements in Latin.
$(b)$ Define Avogadro's constant and molar mass. How are they related to one mole of an atom,molecule,or ion?

(N/A) $(a) (i)$ Examples include Carbon $(C)$ and Nitrogen $(N)$.
$(ii)$ Examples include Sodium ($Na$,from Natrium) and Iron ($Fe$,from Ferrum).
$(b)$ Avogadro's constant: The value $6.022 \times 10^{23}$ is defined as Avogadro's constant $(N_A)$. It represents the number of particles (atoms,molecules,or ions) present in one mole of any substance.
Molar mass: The mass of $1$ mole of a substance in grams is called its molar mass.
Relationship: One mole of any species (atoms,molecules,or ions) contains $6.022 \times 10^{23}$ number of particles,and its mass is equal to its relative atomic or molecular mass expressed in grams.

$1$ mole of particles

Number of particles = $6.022 \times 10^{23}$

Mass = Molar mass in grams