Question

use the periodic table and observe the element with a mass of 35. if the atomic mass number of an atom is 35, which statement is most accurate?
a the number of protons does not equal the number of neutrons.
b the atomic number is less than 16.
c the atom has 20 neutrons.
d the atomic number is over 35.

Explanation:

Step1: Recall the relationship between atomic mass number, atomic number (proton number), and neutron number

The formula is \( \text{Atomic mass number} = \text{Atomic number}+\text{Neutron number}\). Let the atomic number be \(Z\) and the neutron number be \(N\), so \(A = Z + N\), where \(A = 35\).

Step2: Analyze each option

• Option A:

If \(A=35\), assume \(Z = 17\) (from the periodic table, chlorine has \(A\approx35\)). Then \(N=A - Z=35 - 17 = 18\). So \(Z
eq N\).

• Option B:

For chlorine, \(Z = 17>16\).

• Option C:

If \(A = 35\) and \(Z = 17\), \(N=35 - 17=18
eq20\).

• Option D:

Since \(A=Z + N\) and \(N\geq0\), \(Z\leq A\). So \(Z\leq35\).

Answer:

A. The number of protons does not equal the number of neutrons.