Elements CER v2
You have been provided with the observations and measurements of two unknown element samples. Based on your knowledge of the periodic table, element properties, trends, and reactivity, you will identify both elements and explain your reasoning using a Claims-Evidence-Reasoning (CER) framework. After identifying the elements, you will compare each unknown element to another element or group of elements based on 2-3 common properties.
Group 1
Imagine you are a chemist analyzing two unknown element samples. The following observations and measurements were made for each:
Unknown Element #14:
Atomic number: Between 5 and 15 Atomic weight: Between 10 and 30 amu State at room temperature: Gas Conducts electricity: No Reactivity: Reacts to form acids and salts, bonds with metals and hydrogen Color/Appearance: Colorless, odorless gas Periodic trends: Nonmetal, diatomic molecule, high electronegativity Other observations: Supports combustion and is essential for respiration
Unknown Element #6: Atomic number: Between 15 and 20 Atomic weight: Between 30 and 40 amu State at room temperature: Solid Conducts electricity: No Reactivity: Reacts with metals to form salts, forms anions Color/Appearance: Solid, white crystalline form in pure state Periodic trends: High electronegativity, nonmetal Other observations: Commonly found in compounds as a part of fertilizers
Question 1a
Using the Claims-Evidence-Reasoning (CER) format, write a paragraph for each element (2 paragraphs total) identifying which elements you believe the samples are, based on the given data. After identifying both elements, compare each unknown element to another element or group of elements based on 2-3 common properties (e.g., reactivity, state, electronegativity, metallic behavior). Your reasoning should focus on similarities and differences with respect to these properties.
For each element:
- Claim: Clearly state which element you think the unknown sample is.
- Evidence: Provide at least 3 specific pieces of evidence from the list of observations and measurements that support your claim.
- Reasoning/Comparison: Compare the unknown element to another element or group of elements (such as a family or period on the periodic table) based on 2-3 similar or different properties (such as reactivity, state, metallic behavior, or electronegativity). Explain how these comparisons further support your claim.
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