1. The following statements concern the structure of the atom. Which is the correct statement?
A. Protons, neutrons and electrons are almost identical in size.
B. The nucleus is always neutral.
C. Electrons are held stationary in fixed positions around the nucleus.
D. The number of neutrons might not equal the number of protons.
2. Isotopes are atoms that have:
A. an equal number of protons and neutrons
B. the same number of neutrons but different atomic numbers
C. the same atomic number but different mass numbers
D. complete outer shells
3. The number of neutrons in the ion is:
A. 29
B. 64
C. 35
D. 27
4. Why do atoms of particular elements emit a distinctive colour when they (or their vapours) are heated in a flame?
A. The characteristic colours arise because electrons in atoms occupy definite energy levels, When a substance is cooled to a lower temperature, electrons absorb energy and jump from their ground state to higher energy levels.
B. The light is emitted when the elcectrons drop back down to the original energy level
C. The atom colour is brighter in hotter temperatures.
D. Atoms are all a particular colour.
5. The most abundant (mass percentage) atom present in nature, on the Earth is:
A. oxygen
B. silicon
C. sulfur
D. iron
A. Protons, neutrons and electrons are almost identical in size.
B. The nucleus is always neutral.
C. Electrons are held stationary in fixed positions around the nucleus.
D. The number of neutrons might not equal the number of protons.
2. Isotopes are atoms that have:
A. an equal number of protons and neutrons
B. the same number of neutrons but different atomic numbers
C. the same atomic number but different mass numbers
D. complete outer shells
3. The number of neutrons in the ion is:
A. 29
B. 64
C. 35
D. 27
4. Why do atoms of particular elements emit a distinctive colour when they (or their vapours) are heated in a flame?
A. The characteristic colours arise because electrons in atoms occupy definite energy levels, When a substance is cooled to a lower temperature, electrons absorb energy and jump from their ground state to higher energy levels.
B. The light is emitted when the elcectrons drop back down to the original energy level
C. The atom colour is brighter in hotter temperatures.
D. Atoms are all a particular colour.
5. The most abundant (mass percentage) atom present in nature, on the Earth is:
A. oxygen
B. silicon
C. sulfur
D. iron
-
D. The number of neutrons might not equal the number of protons.
C. the same atomic number but different mass numbers
3.) what ion?
B. The light is emitted when the elcectrons drop back down to the original energy level
A. oxygen
C. the same atomic number but different mass numbers
3.) what ion?
B. The light is emitted when the elcectrons drop back down to the original energy level
A. oxygen