Pl: Choose the correct answer

$1-$ The "magic numbers" according to shell model are

a$.$ Numbers of electrons that confer atomic stability.

b$.$ Numbers of protons and$/$or neutrons that confer nuclear stability

c$.\frac{n}{p}$ ratios that confer nuclear stability.

d$.$ Atomic masses that confer nuclear stability.

$2-$ The radius of bismuth$-210,r,=1\mathrm{.}2{10}^{{?}^{{?}^{?}}}-15m$ is

a$.7\mathrm{.}132{10}^{{?}^{{?}^{?}}}-15cm$

b$.7\mathrm{.}132{10}^{{?}^{{?}^{?}}}-13cm$

c$.7\mathrm{.}132{10}^{{?}^{{?}^{?}}}+13m$

d$.7\mathrm{.}132{10}^{{?}^{{?}^{?}}}+15m$

$3.$ Given the following mass doublet values, compute the corresponding values for the atomic mass of ${?}^{84}Sr$ : $($Use: ${(}^{12}C)=12\mathrm{.}000000u,m{(}^{1}H)=1\mathrm{.}00782503u)$

$(C_6{H}_{12})-m{(}^{84}Sr)=0\mathrm{.}180583+-0\mathrm{.}000023u$

a$)83\mathrm{.}19332532u.$

b$)83\mathrm{.}91331736u.$

c$)83\mathrm{.}99331752u.$

d$)83\mathrm{.}63322752u.$

$4-$ The atomic mass of proton with mass $1\mathrm{.}00728U$ equal to

a$.1\mathrm{.}6749{10}^{{?}^{{?}^{?}}}+27kg$

b$.1\mathrm{.}6720{10}^{{?}^{{?}^{?}}}-27kg$

c$.9\mathrm{.}1095{10}^{{?}^{{?}^{?}}}-31kg$

d$.7\mathrm{.}132{10}^{{?}^{{?}^{?}}}+15Kg$

$5-$Nuclei of the same element that have same atomic numbers but different mass number are called:

a$.$ Ions

b$.$ Isotopes

c$.$ Isotones

d$.$ Isobars

$6.$ Atoms with odd atomic number have Nuclear spin:

a$.$ Integral

b$.$ Half$-$integral Zero

c$.$ Zero

d$.$ None of these