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Halogens are elements found in Group VIIA (17) of the periodic table. These elements include fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and astatine (At). Halogens are highly reactive, especially with alkali metals and alkaline earth metals, and readily form salts such as sodium chloride (NaCl). Related Questions: Write the valence shell electronic configuration … Read more
An element in the 3rd period and Group IIA is Magnesium (Mg). Its atomic number is 12, and its electronic configuration is:1s² 2s² 2p⁶ 3s².This indicates that the valence electrons are in the 3s orbital, with two electrons. Related Questions: Define halogens. Which atom has a higher shielding effect, Li or Na? Explain why Na … Read more
The atomic symbol “Al” tells us: Element: The element is Aluminum. Atomic Number: Aluminum has an atomic number of 13, meaning it has 13 protons and 13 electrons in a neutral atom. Mass Number: The mass number (atomic mass) can be deduced from the isotope being referenced, typically 27 for the most common isotope of … Read more
(a) How many protons and electrons does an atom of this element have? Protons: The atomic number is 23, so it has 23 protons. Electrons: In a neutral atom, the number of electrons equals the number of protons, so it has 23 electrons. (b) How many neutrons does this atom have? Neutrons = Mass number … Read more
Medicine: Radioactive isotopes are used for medical imaging and cancer treatment (e.g., iodine-131 for thyroid cancer). Dating: Carbon-14 is used in radiocarbon dating to estimate the age of ancient artifacts and fossils. Energy: Uranium-235 and plutonium-239 are used as fuel in nuclear reactors. Agriculture: Isotopes are used to track the movement of nutrients in plants … Read more
(a) Si (Silicon, Atomic Number 14) 1s² 2s² 2p⁶ 3s² 3p² (b) Mg (Magnesium, Atomic Number 12) 1s² 2s² 2p⁶ 3s² (c) Ar (Argon, Atomic Number 18) 1s² 2s² 2p⁶ 3s² 3p⁶ Related Questions: The electronic configurations listed below are incorrect. Explain the mistakes in each and write the correct electronic configurations. Draw Bohr’s Model … Read more
(a) Potassium (Atomic No. 19, Mass No. 39) Protons: 19 Neutrons: 39 – 19 = 20 Electrons: 19 The Bohr model would show 19 electrons arranged in 4 shells: K shell (1s): 2 electrons L shell (2s, 2p): 8 electrons M shell (3s, 3p): 8 electrons N shell (4s): 1 electron (b) Silicon (Atomic No. … Read more
(a) 2s, 2p Answer: The 2s orbital is lower in energy than the 2p orbital. Generally, s orbitals have lower energy than p orbitals in the same shell. (b) 3p, 2p Answer: The 2p orbital is lower in energy than the 3p orbital. Higher principal quantum numbers correspond to higher energy levels. (c) 3s, 4s … Read more
z = 1s, 2s, 2p, 3s’ Mistake: The configuration ends with 3s’, which is incorrect because the electron configuration of the 3rd shell should fill the 3s sub-shell first before moving to higher sub-shells such as 3p. Correct configuration: 1s² 2s² 2p⁶ 3s² x = 1s, 2s, 2p’, 3p’ Mistake: The configuration mentions 2p’ and … Read more
The sub-shells of the M shell in order of increasing energy are: 3s < 3p < 3d Related Questions: How many sub-shells are there in the N shell? Why is an atom electrically neutral? Give notation for sub-shells of the M shell. The electronic configurations listed below are incorrect. Explain the mistakes in each and … Read more