Q: Which of the following is the correct formula to calculate the charge of an ion?

$$\text{ion charge} = \#p - \#e$$

Question 1

Which statement best describes the difference between an atom and an element?

Accepted Answer

An atom is the smallest identifiable unit of an element, while an element is a substance that cannot be broken down into simpler substances.

Question 2

According to Dalton’s atomic theory, which of the following statements is FALSE?

Accepted Answer

Atoms can be divided into smaller, destructible particles during chemical reactions.

Question 3

J.J. Thomson’s experiments led to the discovery of which subatomic particle, and what was its key property?

Accepted Answer

Electron; negatively charged and much smaller and lighter than atoms.

Question 4

Rutherford’s gold foil experiment disproved the plum-pudding model of the atom. What observation led to this conclusion?

Accepted Answer

Some alpha particles were deflected at sharp angles, indicating a dense, positively charged nucleus.

Question 5

Which of the following best explains why matter is usually electrically neutral?

Accepted Answer

Matter contains equal numbers of positive and negative charges that cancel each other out.

Question 6

An atom of sodium (Na) has 11 protons and 12 neutrons. What is its atomic number and mass number?

Accepted Answer

Atomic number $$Z = 11$$, mass number $$A = 23$$

Question 7

Which property is NOT characteristic of metals?

Accepted Answer

Tend to gain electrons during chemical changes

Question 8

Which group of elements is most likely to form ions with a $$1+$$ charge?

Accepted Answer

Alkali metals

Question 9

A fluorine atom has 9 protons and 9 electrons. If it gains one electron, what is the charge of the resulting ion?

Accepted Answer

$$1-$$

Question 10

Which of the following elements is a metalloid and is widely used in the electronics industry due to its semiconductor properties?

Accepted Answer

Silicon (Si)

Question 11

Which element is defined by having 6 protons in its nucleus?

Accepted Answer

Carbon

Question 12

Which of the following is the correct formula to calculate the charge of an ion?

Accepted Answer

$$	ext{ion charge} = \#p - \#e$$

Question 13

A naturally occurring element consists of two isotopes: 60% isotope A with mass 10 amu and 40% isotope B with mass 12 amu. What is the atomic mass of the element?

Accepted Answer

$$11.2$$ amu

Question 14

Which of the following statements about isotopes is TRUE?

Accepted Answer

Isotopes of an element have the same number of protons but different numbers of neutrons.

Question 15

Which group in the periodic table contains elements that are chemically inert and do not readily form compounds?

Accepted Answer

Noble gases

Question 16

A gallium sample contains 60.11% Ga-69 (mass 68.9256 amu) and 39.89% Ga-71 (mass 70.9247 amu). Calculate the atomic mass of gallium.

Accepted Answer

$$69.72$$ amu

Question 17

Which of the following is a real-world application of radioactive isotopes in medicine?

Accepted Answer

Using technetium-99 to diagnose disease by imaging internal organs.

Question 18

Which scientist is credited with organizing the periodic table based on recurring patterns in element properties?

Accepted Answer

Dmitri Mendeleev

Question 19

Which of the following best describes the difference between cations and anions?

Accepted Answer

Cations are positively charged ions formed by losing electrons, while anions are negatively charged ions formed by gaining electrons.

Question 20

Which of the following elements is named after a scientist?

Accepted Answer

Curium

Atoms and Elements: Foundations of Matter (Chapter 4 Study Notes)

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