To determine which element resembles the one with atomic number 17, we first need to identify the element corresponding to atomic number 17 and then analyze the properties of the other elements listed in the options. ### Step 1: Identify the Element with Atomic Number 17 The element with atomic number 17 is Chlorine (Cl). Chlorine is a halogen, which is a group of elements found in Group 17 of the periodic table. Halogens are known for having similar chemical properties due to their similar electron configurations. ### Step 2: Analyze the Options Now, let's look at the options provided: - **A. 33**: This corresponds to Arsenic (As). - **B. 35**: This corresponds to Bromine (Br). - **C. 18**: This corresponds to Argon (Ar). - **D. 19**: This corresponds to Potassium (K). ### Step 3: Determine Similarities To find which element resembles Chlorine, we need to consider the group and period of each element: - **Chlorine (Cl)** is in Group 17 (the halogens) and Period 3. - **Bromine (Br)** (atomic number 35) is also in Group 17 (the halogens) but in Period 4. Being in the same group means that Bromine shares similar chemical properties with Chlorine, such as reactivity and the formation of similar types of compounds (e.g., both can form halides). ### Step 4: Evaluate the Other Options Now, let’s evaluate why the other options are not correct: - **A. 33 (Arsenic)**: Arsenic is in Group 15 (the nitrogen group) and does not share similar properties with Chlorine. It has a different number of valence electrons (5) compared to Chlorine (7), leading to different chemical behaviors. - **C. 18 (Argon)**: Argon is a noble gas in Group 18. Noble gases are characterized by their lack of reactivity due to having a full valence shell. This is fundamentally different from Chlorine, which is highly reactive and seeks to gain an electron to achieve a stable electron configuration. - **D. 19 (Potassium)**: Potassium is in Group 1 (the alkali metals). Alkali metals have very different properties compared to halogens. They are highly reactive, especially with water, and have only one valence electron, which leads to a completely different set of chemical behaviors. ### Conclusion The correct answer is **B. 35 (Bromine)** because it is in the same group as Chlorine and shares similar chemical properties. The other options do not resemble Chlorine due to their different groups and chemical behaviors. ### Revision Summary - Chlorine (atomic number 17) is a halogen in Group 17. - Bromine (atomic number 35) is also a halogen and shares similar properties with Chlorine. - Arsenic (33), Argon (18), and Potassium (19) belong to different groups and exhibit different chemical behaviors. - Elements in the same group of the periodic table typically have similar chemical properties due to their similar electron configurations.