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12 Cards in this Set

  • Front
  • Back
Name the sub-atomic particles present in an atom.
proton, electron, neutron
Describe 2 characteristics of proton
It is positively-charged and is located in the nucleus.
Explain why atoms are electrically neutral.
Atoms have equal number of protons and electrons, hence the positive charge will cancel out the negative charge.
Define atomic number / proton number.
The number of protons in an atom.
Define mass number / nucleon number.
The number of protons and neutrons in the nucleus of an atom.
Describe briefly how electrons are arranged in an atom.
Electrons are arranged in electron shells, where they can take in a fixed number of electrons.
State the maximum number of electrons in the 1st, 2nd and 3rd shell respectively.
1st shell: 2 electrons
2nd shell: 8 electrons
3rd shell: 8 electrons
Determine the number of neutrons in Si atom.
From the Periodic Table, we observe that the proton number of silicon is 14 and the mass number is 28.
Hence, the number of neutrons is 14 (28 -14)
What do you understand by outermost electrons?
Outermost electrons are found at the last shell of the atom.
Also known as valence electrons.
What is the significance of outer electrons / valence electrons in an atom?
The number of outer electrons determine the chemical properties of the atom.
What is the relationship between the number of outer electrons and the position of the atom in the Periodic Table?
The number of outer electrons correspond to the Group number where the atom is placed.
what is the relationship between the number of electron shells to the location of the atom in the Periodic Table?
The number of electron shells in the atom correspond to the Period in which the atom is placed.