Question

question 18 (1 point)
number of neutrons in sn 118 is

blank 1

question 16 (1 point)
which is the most abundant element on the earth (including the crust, oceans, and atmosphere)?

a hydrogen
b carbon
c oxygen
d iron
e silicon

Explanation:

Question 15 (about neutrons in \( \ce{Sn^{118}} \))

Step1: Recall the formula for neutrons

The number of neutrons (\( n \)) in an atom is given by \( n = A - Z \), where \( A \) is the mass number and \( Z \) is the atomic number. For tin (Sn), the atomic number \( Z = 50 \) (from the periodic table), and the mass number \( A = 118 \) (given as \( \ce{Sn^{118}} \)).

Step2: Calculate the number of neutrons

Substitute \( A = 118 \) and \( Z = 50 \) into the formula: \( n = 118 - 50 = 68 \).

Oxygen is the most abundant element in the Earth's crust, oceans, and atmosphere. In the crust, it's a major component of silicates and oxides; in oceans, it's in water (\( \ce{H2O} \)); in the atmosphere, it's a significant gas. Hydrogen is abundant in water but not as overall as oxygen. Carbon, iron, and silicon are less abundant than oxygen in the combined Earth systems (crust, oceans, atmosphere).

Answer:

68

Question 16 (most abundant element on Earth)