NY Regents Chemistry Exam June 2022
The graph below represents the atomic radii of the elements in Period 3 on the Periodic Table of the Elements.
54 State the general trend for the atomic radius of the first seven elements in Period 3 when considered in order from left to right. [1]
The atomic radius increases as we go from right to left and down on the Periodic Table. This fact can be memorized or you can use Table S to find the atomic radius of elements and see what the trend is. We can slo use the graph given.
Answer : The atomic radius decreases from left to right on the Periodic Table
55 State, in terms of valence electrons, why aluminum and sulfur have different chemical properties. [1]
Elements with the same number of valence electrons have similar chemical properties. Since Aluminum and sulfur have different chemical properties they have different numbers of valence electrons.
Answer: Aluminum and sulfur have a different number of valence electrons.
56 Identify the element in Period 3 that reacts with oxygen to form an ionic compound represented by X in the formula X2O. [1]
Period 3 is row 3 on the Periodic Table. An ionic compound consists of a metal with a nonmetal. Oxygen is a nonmetal (to the right of the staircase on the Periodic Table). Therefore, we're looking for a metal (left of the staircase). Moreover, for ionic compounds charges get cross multiple to arrive at the formula. The formula is X2O. Oxygen has a charge of -2 which is why we see 2 next to X in the formula. Since Oxygen has 1 next to it (1 is not shown), the charge of X must be +1, which is Group 1 on the Periodic Table.
Answer: Na (sodium )
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