An electric device delivers a current of [tex]$15.0 A$[/tex] for 30 seconds. How many electrons flow through it?
Answer (1)
Silicon (Si) is in Period 3 and has a valency of 4.
Sodium (Na) is the most reactive metal because it easily loses its one valence electron.
Sodium (Na) is a metal, and Chlorine (Cl) is a non-metal.
Neon (Ne) is an inert element due to its complete outer electron shell; Chlorine (Cl) is in Group 17, and Sodium (Na) and Hydrogen (H) are in Group 1.
The final answers are based on the analysis of the periodic table and electronic configurations.
Explanation
Problem Analysis Let's analyze the given periodic table and electronic configurations to answer the questions.
Identifying Silicon From the periodic table, the element in Period 3 with valency 4 is Silicon (Si). Its atomic number is 14, so it has 14 protons and 14 electrons. The electronic configuration is 2, 8, 4.
Sketching Atomic Structure The atomic structure of Silicon (Si) has a nucleus with 14 protons and 14 neutrons (typically, though isotopes exist with different numbers of neutrons). Around the nucleus, there are three electron shells. The first shell has 2 electrons, the second has 8 electrons, and the third has 4 electrons.
Identifying Reactive Metal The most reactive metal in the given section is Sodium (Na). This is because it is in Group IA (alkali metals) and has only one valence electron, which it readily loses to form a stable ion. Reactivity increases down Group IA.
Analyzing Electronic Configurations Now, let's analyze the electronic configurations: A. 2, 8, 1 - This is Sodium (Na), a metal. B. 2, 8 - This is Neon (Ne), an inert gas. C. 2, 8, 7 - This is Chlorine (Cl), a non-metal. D. 1 - This is Hydrogen (H), which can behave as a metal or non-metal depending on the conditions.
Identifying Metal and Non-metal From the electronic configurations, a metal is Sodium (Na) and a non-metal is Chlorine (Cl).
Identifying Inert Element Element B (2, 8) is inert because it has a complete outer electron shell (octet), making it stable and unreactive. It is Neon (Ne).
Identifying Group 17 and Group 1 Elements Element C (2, 8, 7) is in group 17 because it has 7 valence electrons. Element A (2, 8, 1) and D (1) are in group 1 because they have 1 valence electron.
Final Answers Therefore, the answers are as follows:
Element in Period 3 with valency 4: Silicon (Si)
Most reactive metal: Sodium (Na), due to having one valence electron easily lost.
Metal: Sodium (Na)
Non-metal: Chlorine (Cl)
Inert element: Neon (Ne), due to complete outer shell.
Group 17: Chlorine (Cl)
Group 1: Sodium (Na) and Hydrogen (H)
Examples
Understanding the periodic table and electronic configurations helps us predict how elements will react with each other. For example, knowing that Sodium (Na) readily loses an electron and Chlorine (Cl) readily gains one helps us understand why they combine to form Sodium Chloride (NaCl), common table salt. This knowledge is crucial in chemistry for designing new materials and understanding chemical reactions.
