Q: Which of the following is a correct atomic symbol for an isotope of magnesium with 12 protons and 14 neutrons?

$$\displaystyle \frac{26}{12}\text{Mg}$$

Question 1

Which of the following statements best describes an element?

Accepted Answer

An element is a pure substance that cannot be broken down into simpler substances.

Question 2

Which element is represented by the symbol 'Ti' and is named after mythological Titans?

Accepted Answer

Titanium

Question 3

What is the group number and period number for calcium (Ca) in the periodic table?

Accepted Answer

Group 2, Period 4

Question 4

Which of the following elements is a noble gas?

Accepted Answer

Neon

Question 5

Which group contains highly reactive elements that form compounds with most other elements and includes chlorine and iodine?

Accepted Answer

Halogens

Question 6

Which of the following is a correct atomic symbol for an isotope of magnesium with 12 protons and 14 neutrons?

Accepted Answer

$$\displaystyle \frac{26}{12}	ext{Mg}$$

Question 7

Which element is a metalloid and is used as a semiconductor in electronics?

Accepted Answer

Silicon

Question 8

A neutral atom of fluorine has how many protons and electrons?

Accepted Answer

9 protons and 9 electrons

Question 9

Which of the following best describes isotopes?

Accepted Answer

Atoms of the same element with different numbers of neutrons

Question 10

Calculate the atomic mass of magnesium given the following data: $$\displaystyle \frac{24}{12}	ext{Mg} (78.70$$%, 23.99 amu), $$\displaystyle \frac{25}{12}	ext{Mg} (10.13$$%, 24.99 amu), $$\displaystyle \frac{26}{12}	ext{Mg} (11.17$$%, 25.98 amu).

Accepted Answer

24.31 amu

Question 11

Which element is found in the compound NaHCO$$_3 ($$baking soda)?

Accepted Answer

Sodium

Question 12

Which of the following statements about ionization energy is correct?

Accepted Answer

Ionization energy increases as you move from left to right across a period.

Question 13

Which element has a larger atomic radius: potassium (K) or lithium (Li)?

Accepted Answer

Potassium (K)

Question 14

Which element is classified as an alkaline earth metal and is located in period 2?

Accepted Answer

Beryllium

Question 15

How many valence electrons does tin (Sn) have?

Accepted Answer

4

Question 16

Which of the following elements is a transition metal?

Accepted Answer

Copper (Cu)

Question 17

Which element is essential for the formation of hemoglobin and is required in the largest quantity among trace elements in the human body?

Accepted Answer

Iron

Question 18

Which of the following best explains why noble gases are unreactive?

Accepted Answer

They have a full set of valence electrons.

Question 19

Which element has the highest ionization energy in period 2?

Accepted Answer

Neon

Question 20

A neutral atom of calcium-42 ($$\displaystyle \frac{42}{20}	ext{Ca}) $$has how many neutrons?

Accepted Answer

22

Atoms and Elements: Structure, Properties, and Periodic Trends

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