Proton: Definition, Quarks, & Charge

Introduction

• A proton is one of the fundamental particles that make up the nucleus of an atom.
• It plays a crucial role in determining the properties of chemical elements.

Structure of a Proton

• A proton is composed of three smaller particles known as quarks.
• The specific combination of quarks in a proton is as follows:
  • Two Up Quarks: These are positively charged quarks.
  • One Down Quark: This is a negatively charged quark.

Charge of a Proton

• Quarks possess fractional electric charges, which are quantised in units of the elementary charge (e).
• The electric charge of a proton is determined by the charges of its constituent quarks.
• The elementary charge (e) is approximately equal to $1.602 \times 10^{-19}$ Coulombs (C).

Calculating the Charge of a Proton

• To calculate the charge of a proton, we can use the charges of the quarks:
  • Two Up Quarks: $+2/3e$ each
  • One Down Quark: $-1/3e$
• The total charge of a proton (Q) can be expressed as:
  • Q = $(2/3e) + (2/3e) + (-1/3e)$
  • Q = $(4/3e) - (1/3e)$
  • Q = $(3/3e)$
  • Q = e
• Therefore, the charge of a proton is equal to the elementary charge (e).

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Proton: Definition, Quarks, & Charge

Significance of Proton Charge

• The positive charge of a proton is crucial for maintaining the electrical balance within the nucleus of an atom.
• Protons interact with electrons, which have an equal but opposite charge, to form electrically neutral atoms.
• The number of protons in an atom's nucleus defines its atomic number, determining its chemical identity.

Summary