1 The study of atomic structure helps to understand: A Weather B Chemical behavior C Biology D Geography
2 Zayn is studying relative atomic mass. He learns that chlorine has two isotopes: chlorine-35 (75% abundance) and chlorine-37 (25% abundance). What is the relative atomic mass of chlorine? A 35.0 amu B 35.5 amu C 37.0 amu D 36.0 amu
3 Mohamed is learning about isotopes. He understands that isotopes are atoms of the same element with different mass numbers. What is the reason for this difference? A Different number of protons B Different number of electrons C Different number of neutrons D Different number of nuclei
4 Julia is studying electronegativity. She knows it is the ability of an atom to attract electrons in a chemical bond. As we move across a period from left to right, electronegativity generally: A Decreases B Increases C Stays the same D First increases then decreases
5 Victor is studying the melting points of metals and non-metals. He notes that most metals have high melting points, while non-metals have lower melting points. Which of the following has a high melting point? A Chlorine B Sulfur C Iron D Oxygen
6 Nora is studying transition elements. She notes that they have high melting points, high density, and form colored compounds. Which of the following is a characteristic property of transition elements? A Low density B Low melting points C Variable oxidation states D Form colorless compounds
8 Fatima is reviewing atomic structure and subatomic particles. She knows that electrons are found outside the nucleus. What is the approximate mass of an electron compared to a proton? A Approximately equal B About 1/1836 of a proton C Twice the mass of a proton D About 1/1000 of a proton
9 Mohamed is learning about the nucleus. He understands that the nuclear force holds the nucleus together. Why is the nuclear force necessary? A To overcome the attractive force between protons and electrons B To overcome the repulsive electrostatic force between protons C To keep electrons in orbit D To separate neutrons from protons
10 Isotopes are atoms of the same element having: A Different atomic numbers B Different mass numbers C Different protons D Different electrons
11 Zara is studying the density of halogens. She notes that the density of halogens increases down the group. At room temperature, chlorine is a gas, bromine is a liquid, and iodine is a solid. What is the state of fluorine at room temperature? A Solid B Liquid C Gas D Plasma
12 Julia is studying the electronegativity of elements. She compares chlorine and bromine. Which element is more electronegative? A Chlorine B Bromine C Both have the same electronegativity D Cannot be determined
14 David is studying Bohr's atomic model. He learns that Bohr proposed specific orbits for electrons. What is a key postulate of Bohr's model? A Electrons can have any energy value B Electrons move in circular orbits with fixed energy levels and can jump between them by absorbing or emitting energy C Electrons are spread out in a cloud around the nucleus D The nucleus contains protons and electrons
15 Metals are generally found on which side of the periodic table? A Right side B Left side C Center only D Bottom only
16 Fatima is learning about the shielding effect. She understands that inner electrons shield outer electrons from the full attraction of the nucleus. As we move down a group, the shielding effect: A Decreases B Increases C Stays the same D First increases then decreases
19 David is learning about the electronic configuration of elements. He knows that the electronic configuration of sodium is 2,8,1. How many valence electrons does sodium have? A 1 B 2 C 3 D 8
20 Emma is studying the periodic table and notices that Group 2 elements have 2 valence electrons. She predicts that they will form ions with a +2 charge. What is the name of Group 2? A Alkali metals B Alkaline earth metals C Halogens D Noble gases
21 Nadia is studying isotopes of carbon. She learns that carbon-12 and carbon-14 are isotopes. What is the difference between carbon-12 and carbon-14? A Carbon-14 has 2 more protons than carbon-12 B Carbon-14 has 2 more neutrons than carbon-12 C Carbon-14 has 2 more electrons than carbon-12 D Carbon-14 has 2 fewer neutrons than carbon-12
23 Rania is studying relative atomic mass. She learns that it is the weighted average mass of an atom compared to 1/12th of carbon-12. What unit is used for relative atomic mass? A Grams B Atomic mass unit (amu) C Kilograms D Moles
24 Yara is learning about radioactivity. She understands that radioactive isotopes have unstable nuclei. What type of radiation is commonly emitted by radioisotopes? A Alpha, beta, and gamma radiation B Only alpha radiation C Only beta radiation D X-rays only
25 Ahmed is learning about early atomic models in his chemistry class. His teacher explains that John Dalton proposed the first scientific atomic theory. According to Dalton's model, what did he propose about atoms? A Atoms are divisible and can be split into smaller particles B Atoms are indivisible, solid spheres that cannot be created or destroyed C Atoms contain a nucleus with protons and neutrons D Atoms have electrons orbiting in fixed energy levels
26 Qasim is learning about isotopes of uranium. He learns that uranium-235 and uranium-238 are both isotopes. Which isotope is commonly used in nuclear reactors? A Uranium-238 B Uranium-235 C Uranium-236 D Uranium-239
29 The modern atomic model is based on: A Bohr theory only B Quantum mechanics C Dalton theory D Rutherford theory
30 Khalid is studying the metallic character of elements in Group 14. He knows that carbon is a non-metal, silicon is a metalloid, and tin and lead are metals. Which element is the most metallic in Group 14? A Carbon B Silicon C Tin D Lead