Chemistry Chapter 2 Test

Examples of Physical: conductivity, magnetic, basic or acidic, luster, malleable, ductile
Examples of Chemical: reacts with HCl, reacts with oxygen

Examples of Physical: conductivity, magnetic, basic or acidic, luster, malleable, ductile
Examples of Chemical: reacts with HCl, reacts with oxygen

The number of electrons in an atom is equal to the number of protons, so if there are 5 protons, there must be 5 electrons. The number of neutrons can vary, but in this case, there are 6 neutrons. Therefore, the correct answer is Electrons = 5, Neutrons = 6, Protons = 5.

Protons are located in the center of the atom, specifically in the nucleus. The nucleus is the small, dense region at the center of an atom where protons and neutrons are found. This is where most of the mass of the atom is concentrated. The electron cloud, on the other hand, surrounds the nucleus and contains the electrons, which are negatively charged particles. Therefore, the correct answer is "The center."

A scientific law is a statement that describes a natural phenomenon or behavior based on repeated observations and experiments. It provides an explanation for the observations made and helps to understand the underlying principles or rules governing the phenomenon. Scientific laws are derived from empirical evidence and are considered to be universally applicable. They serve as a foundation for scientific theories and can be used to predict future observations or outcomes.

Isotopes are atoms of the same element that have different numbers of neutrons. Carbon-12 and carbon-14 are isotopes of each other because they both have the same number of protons (6) but different numbers of neutrons. Carbon-12 has 6 neutrons, while carbon-14 has 8 neutrons.

Protons are in the center of the atom

Squishing a lemon to make lemonade is a physical change because it involves a change in the physical state or appearance of the lemon. The lemon is being physically crushed or squished, but its chemical composition remains the same. The lemonade is made by extracting the juice from the lemon, which is a physical process. Therefore, this is a physical change.

The object turning white in the air is a chemical property. Chemical properties describe how a substance reacts with other substances to form new substances. In this case, the orange object undergoes a chemical reaction with the air, causing it to change color and turn white. This indicates that there is a chemical change happening in the object.

13th column 3 electrons

The beam is negatively charged so it's made up of electrons

In a chemical reaction, atoms are rearranged to form new substances, but the total number of atoms remains constant. This is known as the law of conservation of mass. Therefore, the total number of atoms after the reaction will be the same as the total number of atoms before the reaction.

Bohr is the correct answer because he proposed the concept of energy levels in atoms. In 1913, Niels Bohr introduced his atomic model, which stated that electrons orbit the nucleus in specific energy levels or shells. These energy levels are quantized, meaning that electrons can only exist in certain discrete energy states. This model successfully explained the stability of atoms and the emission and absorption of light. Bohr's discovery of energy levels revolutionized our understanding of atomic structure and laid the foundation for modern quantum mechanics.

The atomic mass of an element is the weighted average of the masses of all its isotopes, taking into account their relative abundance. In this case, the element has two isotopes, one with a mass number of 25 and the other with a mass number of 27. The isotope with mass number 25 makes up 30% of the element, while the isotope with mass number 27 makes up 70%. To find the atomic mass, we can calculate the weighted average using the formula: (30% x 25) + (70% x 27) = 26.5. Therefore, the closest atomic mass to this element is 26.5.

The correct answer is that the atoms in the chunk of gold and the thin sheet of gold would be the same. This means that regardless of whether the gold is in chunk form or in a thin sheet, the individual atoms that make up the gold will be identical.

The ability of an element to react with oxygen and form an oxide is a chemical property because it involves a chemical change. When an element reacts with oxygen, it undergoes a chemical reaction and transforms into a different substance, which is the oxide. This is different from a physical property, which can be observed or measured without changing the identity of the substance. Therefore, the correct answer is that it is a chemical property because when you test it, the element changes into something else.

Electrons are negatively charged and very light compared to protons

The given answer options are all examples of physical changes. A physical change is a change in the physical properties of a substance, where the substance remains the same chemically. In the case of a basketball deflating, the physical property of the basketball (its volume) is changing. Crumpling up an old quiz also changes the physical appearance of the paper, but it is still paper. Breaking a piñata involves physically breaking the object, but it remains the same material. Therefore, all three options are examples of physical changes.

Alpha particles are large and heavy compared to other types of particles, such as electrons. They have a positive charge and high energy. When alpha particles pass through a very thin piece of iron, most of them will pass right through because the iron atoms are mostly empty space. The positive charge of the alpha particles is not strong enough to interact significantly with the iron atoms. Therefore, the majority of the alpha particles will not be deflected or stopped by the iron and will continue on their path.

When a piece of gold is cut into the smallest piece possible, it would be left with a single atom of gold that is too small to be seen. Atoms are the basic building blocks of matter, and they cannot be divided further without losing their identity. Since gold is made up of atoms, cutting it into the smallest piece would result in a single atom. This atom would be too small to be seen with the naked eye due to its microscopic size.

The correct answer is Thomson because his atomic model, also known as the "plum pudding" model, proposed that atoms are composed of positively charged particles with negatively charged electrons embedded within them. This model was based on the discovery of electrons and their properties, and it was a significant contribution to the understanding of atomic structure. Rutherford's model came after Thomson's and proposed the existence of a small, dense nucleus at the center of the atom, while Bohr's model incorporated the concept of energy levels and orbits for electrons. Dalton's atomic theory laid the foundation for modern atomic theory but did not provide a specific model of the atom.

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Rutherford's atom model is the correct answer because he proposed the nuclear model of the atom, also known as the planetary model. In this model, Rutherford suggested that the atom consists of a small, dense, positively charged nucleus at the center, with negatively charged electrons orbiting around it. This model was based on Rutherford's famous gold foil experiment, which showed that most of the atom's mass and positive charge is concentrated in the nucleus.

Ernest Rutherford helped to discover the nucleus. He conducted the famous gold foil experiment in which he bombarded a thin gold foil with alpha particles. Through this experiment, he observed that most of the alpha particles passed straight through the foil, but a few were deflected at large angles. Rutherford concluded that the deflections were due to a small, dense, and positively charged region at the center of the atom, which he called the nucleus. This discovery revolutionized the understanding of atomic structure and paved the way for further advancements in nuclear physics.

The correct answer is Proton and Neutron. Protons and neutrons both have a mass of approximately 1 atomic mass unit (amu). Electrons, on the other hand, have a much smaller mass compared to protons and neutrons, and their mass is usually considered negligible in comparison. Therefore, only protons and neutrons have a mass of 1 amu.

The molar mass (formula mass) for B2(Cr2O7)3 is 669.577 g/mol. This value represents the sum of the atomic masses of all the atoms in one mole of the compound. The compound contains 2 boron atoms, 2 chromium atoms, and 21 oxygen atoms. By multiplying the atomic masses of each element by their respective number of atoms and summing them up, we can calculate the molar mass of the compound.

Molecules are the fundamental building blocks of many substances. They can be composed of atoms of the same element, such as oxygen (O2), or different elements, such as water (H2O). The chemical bonds that hold atoms together in a molecule determine its properties and how it interacts with other substances.

The molar mass (formula mass) for Ca(C2H3O2)2 is 158.1654 g/mol. This value is obtained by adding up the atomic masses of all the atoms in the formula unit. In this case, we have one calcium atom (Ca) with a molar mass of 40.08 g/mol, two acetate ions (C2H3O2) with a molar mass of 59.04 g/mol each. Adding these masses together gives us a total molar mass of 158.1654 g/mol.

The given electron configuration represents the electron distribution in the element Lawrencium (Lr). The numbers and letters in the configuration represent the energy levels (1s, 2s, etc.) and the orbitals (s, p, d, f) within each energy level. The superscript numbers represent the number of electrons in each orbital. Therefore, the electron configuration 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d10 6p6 7s2 5f14 6d1 indicates that Lawrencium has 103 electrons, with the last electron occupying the 6d orbital.

The answer provides a list of patterns that can be observed on the periodic table. These patterns include the element symbol, the number of protons, the block they belong to (S, D, P, F), isotope averages, the number of valence electrons, families or element similarity, classification as metals, non-metals, or metalloids, atomic number, energy level, and electronegativity. These patterns help organize and categorize the elements on the periodic table based on their properties and characteristics.