Question

1. although a meteorite might travel millions of kilometers to reach earth, the particles of iron in a meteorite are identical to the particles of iron in an iron skillet. which statement below is true of iron? a. iron is a pure substance. b. iron is a metalloid. c. iron is a homogeneous mixture. d. iron is an ion. 21. john dalton was an early contributor towards modern atomic theory. through his experimentation he drafted an atomic theory that had 5 parts. which of the following is not part of daltons atomic theory? a. atoms of the same element are identical; because they all react in the same way. b. atoms of different elements are different; because different elements have different properties. c. atoms can be subdivided into smaller subatomic particles; protons, neutrons, and electrons exist in an atom. d. atoms combine in ratios to form compounds; compounds contain a specific amount of atoms from different elements. 22. which of the following describes the contribution to atomic theory made by niels bohr? a. atoms consist of a positively charged nucleus surrounded by negatively charged electrons that travel in quantized orbits around the nucleus. b. atoms consist of a positively charged nucleus surrounded by an electron cloud. c. atoms consist of negatively charged electrons distributed throughout a positively charged region. d. atoms consist of a positively charged nucleus with negatively charged electrons orbiting at various angles and distances around the nucleus. 23. prior to rutherford, the accepted atomic model was the plum pudding model. rutherford conducted an experiment in which he aimed a beam of positively charged alpha particles at very thin gold foil. what were the results of his experiment and how did this expand on the understanding of atomic structure? a. all of the alpha particles went straight through the foil. most of the atom is empty space. b. most of the alpha particles went straight through the foil, but some were deflected. most of the atom is empty space with a dense positive center. c. most of the alpha particles went straight through the foil, but some were absorbed. most of the atom is empty space with a dense negative center. d. most of the alpha particles were deflected. atoms are mostly solid substances. 24. isotopes of an atom consist of the same number of protons and differ in the number of neutrons. the most common isotope of chlorine is chlorine - 35, and consists of 17 protons and 18 neutrons. why is the atomic mass of chlorine on a periodic table 35.453 amu?

Explanation:

Step1: Recall iron properties

Iron is an element and thus a pure substance.

Step2: Understand Dalton's atomic theory

Dalton's theory did not include the idea of subatomic particles.

Step3: Know Bohr's atomic model

Bohr proposed quantized electron orbits around the nucleus.

Step4: Analyze Rutherford's experiment

The deflection of some alpha particles showed a dense positive nucleus and mostly empty space in the atom.

Step5: Consider isotope concept

Atomic mass is a weighted - average of isotope masses based on their abundances.

Answer:

1. A. Iron is a pure substance.
2. C. Atoms can be subdivided into smaller subatomic particles; protons, neutrons, and electrons exist in an atom.
3. A. Atoms consist of a positively charged nucleus surrounded by negatively charged electrons that travel in quantized orbits around the nucleus.
4. B. Most of the alpha particles went straight through the foil, but some were deflected. Most of the atom is empty space with a dense positive center.
5. Chlorine has multiple isotopes. The atomic mass on the periodic - table is the weighted - average of the masses of its isotopes. Chlorine has other isotopes like chlorine - 37 in addition to chlorine - 35. The weighted - average takes into account the relative abundances of these isotopes, resulting in an atomic mass of 35.453 amu.