Question

for each statement below, write (t) true or (f) false.

1. the number of neutrons in an atom is referred to as its atomic number.
2. the periodic table is arranged by increasing atomic number.
3. atomic number is equal to the number of electrons in an atom.
4. the number of protons in an atom identifies it as an atom of a particular ele
5. most atoms have either a positive or a negative charge.

label the mass number and the atomic number on the following isotope notation.
6.
7.
write each isotope below in symbolic notation. use the periodic table to determine the atomic number of each isotope.

1. neon - 22
2. uranium - 234

answer the following questions.

1. lead has an atomic number of 82. how many protons and electrons does lead have if its neutral?
2. oxygen has 10 electrons. how many protons does oxygen have if it has a \ - 2\ charge?
3. polonium has an atomic number of 84. how many protons and electrons does it have if its neutral?
4. how many protons and electrons does calcium have if its got a \2+\ charge?
5. calculate the atomic mass of the element x. then use the periodic table to identify the element. show all your work.

Explanation:

Step1: Calculate the atomic mass

The formula for atomic mass \(M=\sum_{i}(m_i\times p_i)\), where \(m_i\) is the mass of isotope \(i\) and \(p_i\) is the percent abundance of isotope \(i\) (in decimal form).
For \(^{27}X\): \(m_1 = 27.977\), \(p_1=0.9223\)
For \(^{28}X\): \(m_2 = 28.976\), \(p_2 = 0.0467\)
For \(^{29}X\): \(m_3=29.974\), \(p_3=0.0310\)

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Step2: Identify the element

Looking at the periodic table, the element with an atomic mass close to \(28.085\) is silicon (Si).

Answer:

The atomic mass of element \(X\) is approximately \(28.085\) amu and the element is silicon (Si).