Part of the Periodic Table is shown.
Which element is a metal?
▶️ Answer/Explanation
Ans: A
From the periodic table shown in the question (not visible in text), we can deduce:
1. Metals are typically found on the left side and middle of the periodic table.
2. Non-metals are found on the right side.
3. The question indicates that element A is a metal, which would be positioned in the metal region of the periodic table.
Therefore, the correct answer is option A.
Which compound is made from elements that are all in the same period?
A) Al2(SO4)3
B) C2H5OH
C) LiNO3
D) Na3AlF6
▶️ Answer/Explanation
Ans: C
To solve this, we need to check which compound contains elements all from the same period (row) in the Periodic Table.
Option A: Al (Period 3), S (Period 3), O (Period 2) – different periods
Option B: C (Period 2), H (Period 1), O (Period 2) – different periods
Option C: Li (Period 2), N (Period 2), O (Period 2) – all same period
Option D: Na (Period 3), Al (Period 3), F (Period 2) – different periods
Only LiNO3 contains elements that are all in Period 2.
Which statement about the Periodic Table is correct?
A) All the metals in the Periodic Table are transition elements.
B) The halogens are elements in Group I of the Periodic Table.
C) The elements become more metallic across a period from Group I to Group VII.
D) The Periodic Table can be used to predict the properties of the elements.
▶️ Answer/Explanation
Ans: D
Let’s evaluate each option:
- A: Incorrect – There are many metals (like alkali and alkaline earth metals) that aren’t transition elements.
- B: Incorrect – Halogens are in Group VII, not Group I.
- C: Incorrect – Elements become less metallic (more non-metallic) across a period from left to right.
- D: Correct – The Periodic Table organizes elements by atomic number and shows periodic trends in properties, allowing predictions about element behavior.
The Periodic Table’s main purpose is to show periodic trends and allow prediction of element properties based on position.
Which option describes the electronic configurations of three different elements from the same group of the Periodic Table?
A) 2 2,2 2,8,8,2
B) 2 2,8 2,8,2
C) 2,1 2,8,1 2,8,8,1
D) 2,1 2,2 2,3
▶️ Answer/Explanation
Ans: C
Elements in the same group have the same number of valence electrons. Let’s analyze each option:
- Option A: Shows configurations with 2, 2, and 2 valence electrons respectively – but the second element (2,2) is in Group 2 while the third (2,8,8,2) is in Group 2 but the first (2) is helium (Group 18).
- Option B: Shows configurations with 2, 8, and 2 valence electrons – different numbers, so not same group.
- Option C: All configurations end with 1 valence electron (2,1; 2,8,1; 2,8,8,1) – these are all Group 1 elements (alkali metals).
- Option D: Shows 1, 2, and 3 valence electrons respectively – different groups.
Only option C shows three elements all with 1 valence electron, meaning they’re in the same group (Group 1).