Question

1. which statement describes the particles in a liquid? a they are close together but have no regular arrangement. b they are densely packed in a regular order. c they move freely at high speed and are widely spaced. d they vibrate but do not move from a fixed position. 2. which two gases will diffuse at the same rate, at the same temperature? a carbon monoxide and carbon dioxide b carbon monoxide and nitrogen c chlorine and fluorine d nitrogen and oxygen 3. which statement about the periodic table is correct? a elements in the same group have the same number of electron shells. b elements are arranged in order of increasing proton number. c metals are on the right and non - metals are on the left. d the most reactive elements are at the bottom of every group.

Explanation:

1. In a liquid, particles are close together but have no regular arrangement. Solids have particles densely packed in a regular order (B), gases have particles that move freely at high - speed and are widely spaced (C), and in a solid, particles vibrate but do not move from a fixed position (D).
2. According to Graham's law of diffusion, gases with the same molar mass diffuse at the same rate at the same temperature. Carbon monoxide (CO) has a molar mass of approximately 28 g/mol and nitrogen ($N_2$) has a molar mass of approximately 28 g/mol.
3. In the Periodic Table, elements are arranged in order of increasing proton number (atomic number). Elements in the same group have the same number of valence electrons, not electron shells (A). Metals are on the left and non - metals are on the right (C is wrong). The most reactive metals are at the bottom of groups in the s - block, but for the halogens (a non - metal group), the most reactive is at the top (D is wrong).

Answer:

1. A. They are close together but have no regular arrangement.
2. B. carbon monoxide and nitrogen
3. B. Elements are arranged in order of increasing proton number.