Question

how many of the following did dalton not discuss in his atomic theory?
isotopes, ions, protons, electrons, neutrons
a 1
b 5
c 2
d 4
e 3

Explanation:

Step1: Recall Dalton's Atomic Theory

Dalton's atomic theory proposed that atoms are indivisible and indestructible, and all atoms of an element are identical in mass and properties. However, later discoveries showed atoms are divisible (have subatomic particles like protons, electrons, neutrons), can have different masses (isotopes), and can gain/lose charge (ions).

Step2: Analyze each term

• Isotopes: Dalton thought all atoms of an element have same mass, so no discussion of isotopes (different mass same element).
• Ions: Dalton didn't consider atoms gaining/losing charge (ions involve charge change).
• Protons: Dalton didn't know about subatomic particles like protons (thought atoms were indivisible).
• Electrons: Dalton didn't know about electrons (discovered later by Thomson).
• Neutrons: Dalton didn't know about neutrons (discovered later by Chadwick).

Step3: Count the number of terms not discussed

All 5 terms (isotopes, ions, protons, electrons, neutrons) were not discussed in Dalton's atomic theory.

Answer:

b. 5