Question

iron, an element with the chemical symbol fe, is an important element. it is used to make steel and is part of the substance that transports oxygen throughout the human body.
which statement about fe is supported by the modern atomic theory but not john dalton’s theory?
○ the element iron is composed of small particles called atoms.
○ the electrons of iron have probable locations in a region of space around the nucleus.
○ iron atoms combine with other atoms in whole number ratios to form compounds.
○ chemical reactions that involve iron do not create new atoms of iron.

Explanation:

1. Analyze Dalton's atomic theory: Dalton proposed that atoms are indivisible, solid spheres, and had no concept of electrons or electron cloud. Modern atomic theory (quantum model) describes electrons as having probable locations (orbitals) around the nucleus.
2. Evaluate each option:

• Option 1: Dalton's theory also stated elements are made of atoms, so this is supported by both.
• Option 2: Dalton's theory had no idea about electrons or their locations; modern theory (quantum mechanics) describes electrons in regions of space (orbitals) around the nucleus. This is supported by modern theory but not Dalton's.
• Option 3: Dalton's theory included that atoms combine in whole - number ratios to form compounds, so this is supported by both.
• Option 4: Dalton's theory stated that atoms are neither created nor destroyed in chemical reactions, so this is supported by both.

Answer:

B. The electrons of iron have probable locations in a region of space around the nucleus.